Advanced Oxidation Processes

Titanium alloys have been of great interest in recent years because of their very attractive combination of high strength, low density and corrosion resistance. Application of these alloys in areas where wear resistance is also of importance calls for thorough investigations of their tribological properties. In this work, Ti–6Al–4V and Ti–24Al–11Nb alloys were subjected to dry sliding wear against hardened-steel counter bodies and their tribological response was investigated. A pin-on-disc type apparatus was used with a normal load of 15–45N and sliding speed of 1.88 ms−1. In the steady state, it was demonstrated that Ti–24Al–11Nb had a substantially higher wear resistance (about 48 times) than that of the Ti–6Al–4V alloy tested under a normal load of 45 N. Severe delamination is found to be responsible for the low wear resistance of Ti-6Al-4V. In the case of Ti–24Al–11Nb, two wear mechanisms have been suggested: delamination with a lower degree of severity and oxidative wear. It is thought that the ability of Ti–24Al–11Nb to form a protective oxide layer during wear results in a much lower wear rate in this alloy.

— Textile effluent are abundant source of colored pollutant that present an enhancing the environmental danger. So the color present in textile effluent is that major concern of researcher today. Dyestuff present in textile effluent is mainly xenobiotic in nature and not easily self-biodegradable. Intensive treatment is necessary to degrade the dyestuff and reduces the COD and turbidity of textile effluent. The present work is an attempt to review the all possible treatment methods for remove dyestuff from textile effluent by Advanced Oxidation Processes (AOPs). The proposed studies in this paper summarize the capability and potential of conventional treatment for degradation of dyestuff from textile effluent. Conventional method for treatment of textile effluent has own certain limitations that can be well overcome by advance oxidation processes (AOPs).

A massive air or steam ingress in High Temperature Reactors (HTRs) nominally operating at 600-950 o C is a design-basis accident requiring the development and validation of graphite oxidation and erosion models to examine the impact on the potential fission products release and the integrity of the graphite core and reflector blocks. Nuclear graphite is of many types with similarities but also differences in the microstructure, volume porosity, impurities, type and size of filler coke particles, graphitization and heat treatment temperatures, and the thermal and physical properties. These as well as the temperature, types and partial pressures of oxidants affects the prevailing oxidation mode and kinetics of the oxidation processes of graphite in HTRs. This paper reviews the graphite crystalline structure, the fabrication procedures, characteristics, chemical kinetics and modes of oxidation of nuclear graphite for future model developments.

The vacuum-UV (VUV) radiation of water leads to the in situ formation of hydroxyl radicals. Low-pressure mercury vapor lamps which emit at 185 nm are potential sources of VUV radiation. Zoschke et al. [1] presented an excellent discussion of the utilization of VUV radiation at 185 nm for treating water comprising the conversion of inorganic and organic water constituents, and the disinfection performance. One more focal point stays on the production of ozone via VUV radiation from oxygen or air and the usage of the formed ozone in integration with VUV irradiation of water in the VUV/O3 method. This work focuses on the merits and restriction of the VUV technology at 185 nm as well as likely usages in disinfecting water is outlined. Practically, VUV irradiation stays not a true stand by to traditional methods in water treatment, like adsorption on activated carbon, or to diverse advanced oxidation processes (AOPs) because of the inherent restrictions of the VUV technology. Nevertheless, VUV irradiation bids fresh potentials for particular utilization such as the provision of ultrapure water or as a principal treatment method for decentralized setups. Like for many AOPs, the most suitable use in (large-scale) water treatment remains the implementation as a pre-treatment to improve bio-decomposition. [1]

Photocatalysis has been carefully studied in
the last 25 years, thanks to their versatility
in the utilization as a pollutant degradation
process, due to stricter regulations, that are
􀁗􀁋􀁈􀀃 􀁕􀁈􀃀􀁈􀁆􀁗􀁌􀁒􀁑􀀃 􀁒􀁉􀀃 􀁖􀁒􀁆􀁌􀁈􀁗􀁜􀂶􀁖􀀃 􀁓􀁕􀁈􀁒􀁆􀁆􀁘􀁓􀁄􀁗􀁌􀁒􀁑􀀃 􀁒􀁉􀀃
maintaining its environment free of pollutants.
The photocatalysis process is based on the
transfer of charge through the interface
between the semiconductor and the polluted
watery solution. In the interface of these two
components the resultant is a redistribution that
􀁖􀁌􀁊􀁑􀁌􀂿􀁆􀁄􀁑􀁗􀁏􀁜􀀃􀁈􀁛􀁗􀁈􀁑􀁇􀁖􀀃􀁌􀁑􀀃􀁅􀁒􀁗􀁋􀀃􀁖􀁌􀁇􀁈􀁖􀀑􀀃􀀷􀁋􀁈􀀃􀁓􀁕􀁈􀁖􀁈􀁑􀁆􀁈􀀃
of semiconductor is needed in photocatalysis,
in which the conductivity increases with
temperature, but it is less than in metals. One of
the most outstanding aspects is the generation
of electron-hole pair, being this the principle
on which photocatalysis is based, since through
this model the absorption of photons and the
distribution of different electronic states in the
surface is explained. Thanks to this phenomenon
the degradation of organic molecules, colorants,
and metals such as cadmium, nickel, mercury,
copper, chromium, among others, is possible.

Soluble coffee production generates wastewater containing complex mixtures of organic macromole-cules. In this work, a sequential Electrocoagulation-Electrooxidation (EC-EO) process, using aluminum and graphite electrodes, was proposed as an alternative way for the treatment of soluble coffee effluent. Process operational parameters were optimized, achieving total decolorization, as well as 74% and 63.5% of COD and TOC removal, respectively. The integrated EC-EO process yielded a highly oxidized (AOS ¼ 1.629) and biocompatible (BOD 5 /COD z 0.6) effluent. The Molecular Weight Distribution (MWD) analysis showed that during the EC-EO process, EC effectively decomposed contaminants with molecular weight in the range of 10e30 kDa. In contrast, EO was quite efficient in mineralization of contaminants with molecular weight higher than 30 kDa. A kinetic analysis allowed determination of the time required to meet Colombian permissible discharge limits. Finally, a comprehensive operational cost analysis was performed. The integrated EC-EO process was demonstrated as an efficient alternative for the treatment of industrial effluents resulting from soluble coffee production.

The photocatalytic degradation of Toluidine Blue dye (TB) in aqueous solution was investigated under UV light in the presence of magnesium oxide (MgO) as a photocatalyst at different operating parameters. The operating
conditions were photocatalyst dose, initial dye concentration and the pH of the solution. Increasing of photocatalyst dose from 10 to 70 mg enhanced the degradation rate of TB dye. However, the increasing of TB dye concentration from 2 to 8 mg/L negatively affected the degradation rate. It was found that the percent of dye
removal reached the maximum value at high acidic medium. In dark condition, 15 % of dye was adsorbed by MgO. Furthermore, the kinetics involved in the degradation of TB dye was examined and the degradation was found to follow pseudo first order kinetic model.

Three chemical kinetic mechanisms of methane combustion were tested and compared using the internal combustion engine model of Chemkin 4.02 [1]: one-step global reaction mechanism, four-step mechanism, and the standard detailed scheme GRIMECH 3.0. This study shows good concordances, especially between the four-step and the detailed mechanisms in the prediction of temperature and main species profiles. But reduced schemes were incapables to predict pollutant emissions in an internal combustion engine. The four-step mechanism can only predict CO emissions but without good agreement.

http://www.doiserbia.nb.rs/Article.aspx?ID=0354-98360801043E&AspxAutoDetectCookieSupport=1

An oil refinery is an industrial process plant where crude oil is processed and refined into more useful products such as petroleum naphtha, gasoline, diesel fuel, asphalt base, heating oil, kerosene, and liquefied petroleum gas. They  are typically large, sprawling industrial complexes with extensive piping running throughout, carrying streams of fluids between large chemical processing units

The effluents of some pulp and paper processes are potentially pollutant, because of their large volume and their refractory nature. Biological processes generally are not capable to remove these compounds. Advanced Oxidation Processes (AOP) are characterized by the capability of exploiting the high reactivity of HO • radicals. AOP can produce a total mineralization, transforming recalcitrant compounds into inorganic substances (CO 2 and H 2 O 2), or partial mineralization, transforming them into more biodegradable substances. The high reactivity and low selectivity of these radicals are useful attributes that that make these processes in promising technologies. Due to the differences between pulping processes, the effluents from the various processes and operations of such industries also differ from each other, so that some oxidative processes should be combined to improve the removal efficiency. For the effective oxidation of refractory organic compounds, hydroxyl radicals should be generated continuously in situ due to its chemical instability. Generation of HO • is commonly accelerated by combining oxidizing agents. Among these treatments, UV radiation plus hydrogen peroxide (UV/H 2 O 2), Fenton's reagent (H 2 O 2 /Fe +2), photo-Fenton (UV/H 2 O 2 /Fe +2), and ozone in different combinations (O 3 /UV; O 3 /H 2 O 2) are considered to be effective for the oxidation of effluents from pulp and paper industries.

The textile industry is one of the important industries which generates large amount of industrial effluents each year causing the main source of water pollution which is not only harmful for aquatic life but also mutagenic to human. The aim of this work is to give an overview on the health and environmental impact of dyes as pollutants as well as; the most recent treatment techniques of textile effluents wastewater.

Fenton Process, a type of Advanced Oxidation Processes is an efficient method for treating textile
wastewaters. However, excessive use of hydrogen peroxide and catalyst has made this process
economically non-feasible. Besides, industrial grade hydrogen peroxide costs $390 e500 per ton. One of
the means to overcome this problem is the in-situ production of hydrogen peroxide. In this paper, a
detailed review was conducted on the generation methods, degradation potential and optimum operating parameters for in-situ production of hydrogen peroxide/hydroxyl radicals. Additionally the scavenging aspect for hydroxyl radicals was also investigated. From this review, it can be concluded that
hydroxyl radical is highly oxidative and non selective in nature and its in-situ production can be performed through application of catalyst, ozonation, photocatalysis, electro and microbial fuel cells.
Furthermore, optimization of operating parameters can result in an increase in the yield of hydroxyl
radicals/hydrogen peroxide. Sonolysis as an auxiliary tool has potential to induce synergetic effects in
combination with Advanced Oxidation Processes to increase in-situ hydrogen peroxide production.
However, the problem of the scavenging effect is an aspect that needs to be dealt with, as hydroxyl
radicals are prone to deactivation by scavengers. Therefore based on the review, it is concluded that insitu production of hydrogen peroxide/hydroxyl radical for treating textile wastewater is economically
viable and practically feasible if careful selection of process is conducted through selective research

Advanced oxidation is one of the potential alternatives to decolorize and to reduce recalcitrant wastewater loads from textile dyeing and finishing effluents. This process implies generation and subsequent reaction of hydroxyl radicals, which are the most powerful oxidizing species after fluorine. Among AOPs, treatment with ozone (often combined with H 2 O 2 , UV, or both), an UV/H 2 O 2 system, or Fenton and Photo-Fenton type processes have proven to yield very good results either for complete mineralization of reactive dyes or for their transformation into less complex structures that are more easily biodegradable. Particularly, we summarize recent researches in the AOP treatment using O 3 alone and or in combination with UV, US and H 2 O 2 of textile wastewater for complete color and COD removal and decrease the toxicity of the treated wastewater for water.

Removing emerging contaminants from waste streams has become a topic of growing interest. The adverse effects of endocrine disrupting chemicals (EDCs) and pharmaceutical and personal care products (PPCPs) have been well documented, but much remains to be known about these contaminants and their removal. Their removal with traditional methods has not been entirely successful. However, adequate degradation can be achieved through the use of advanced oxidation processes (AOPs). Multiple factors must be considered when completing an in-depth comparison; therefore , process engineering, environmental, and economic and social parameters were included in a deeper analysis. This study presents a ranking system to numerically score the performance of various AOPs (e.g., Ozonation, UV irradiation, Photocatalysis, Fenton reaction, and integrated processes) in several categories of parameters under engineering, environmental, and socioeconomic components. From this preliminary assessment, it was noted that H 2 O 2 /O 3 (Perozonation) presented the highest average ranking (3.45), with other processes showing comparable performance. TiO 2 photocatalysis received the lowest ranking (2.11).

A series of graphene oxide/magnesium oxide nanocomposites (GO/MgO NCs) were and applied for the removal of Methylene Blue (MB) from aqueous solutions. The prepared NCs were characterized using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectrum, X-ray photoelectron spectroscopy, and thermogravimetric analysis. The results showed that MgO particles was successfully decorated on GO. The impacts of different experimental variables on the removal of MB including GO/ MgO NCs dosage, pH, contact time, and initial MB concentration were investigated. The experimental analysis of adsorption isotherms indicated that adsorption data was best fit with the Langmuir isotherm model. Among the three different synthesized weight ratios of GO/MgO (5:1, 1:1, and 1:5), 5:1 ratio showed the maximum ad-sorption capacity as 833 mg/g, which is higher than any previously reported GO-based composites. The synthesized GO/MgO NC is also observed to have higher adsorption capacity for MB removal, in comparison with pure GO and MgO. The kinetic adsorption data was best described by pseudo-second-order kinetic model. The pH of point of zero charge (pH pzc) of GO/MgO NCs was determined to be 9.7, 10.5, and 10.5 for ratios 5:1, 1:1, and 1:5, respectively. The results revealed that electrostatic attraction can be the dominant mechanism of adsorption between GO/MgO NCs and MB for pH above pH pzc ; whereas for pH below pH pzc , other adsorption mechanisms such as hydrogen bonding and π–π interaction may attribute to adsorption. The high adsorption capacity of GO/MgO composites, thus makes it a promising adsorbent for water and wastewater treatment.

This work concentrates on the review paper published by Ahmed et al . [1]
which is dedicated to the elimination of emerging contaminants (ECs) using
biological, chemical and hybrid techniques in effluents from wastewater
treatment plants (WWTPs). Endocrine disruption chemicals (EDCs) are better
reduced by a membrane bioreactor (MBR), activated sludge, and aeration
processes between various biological processes. Surfactants, EDCs and personal
care products (PCPs) may be well reduced using activated sludge
processes. Pesticides and pharmaceuticals manifested convenient reduction
performances by biological activated carbon. Microalgae treatment techniques
may diminish nearly all sorts of ECs to a certain degree. Additional
biological methods were observed less efficient in dealing with ECs. Chemical
oxidation techniques (like ozonation/H2O2, UV photolysis/H2O2, and photo-
Fenton) may greatly eliminate up to 100% of pesticides, beta-blockers, and
pharmaceuticals; at the same time, EDCs may be better reduced via ozonation
and UV photocatalysis. Fenton method was observed less efficient in treating
any sorts of ECs. A merged setup founded on ozonation pursued by biological
activated carbon was manifested hugely efficacious in eliminating pesticides,
beta-blockers, and pharmaceuticals. An integrated ozonation-ultrasound device
may eliminate until 100% of numerous pharmaceuticals. Next research
orientations to boost the elimination of ECs have been suggested.

The release of persistent organic pollutants (POPs) into the environment is an issue of global concern, as the chemicals are stable over a prolonged period resulting in their accumulation in many animals and plants. Although POPs are banned in several countries, many chemicals have been proposed as POP candidates to be added to the existing compounds as defined by the United Nations Stockholm Convention committee. To address the safe disposal and clean-up of such chemicals, new, and especially cost-effective, remediation technologies for POPs are urgently required. This review focuses on existing POPs and the types of remediation processes available for their removal. Particular attention is paid towards photocatalysis using nanocatalysts in this review, due to their effectiveness towards POP degradation, technological feasibility, and energy and cost-efficiency. The underlying principles and the key mechanisms of the photocatalysts based on TiO 2 based materials, metal oxides, light-assisted Fenton systems, framework materials e.g. metal-organic frameworks and polyoxometalates, including metal-free and hybrid photocatalysts for POPs cleanup are described for advance applications in solving the POPs contamination in

Pollution provoked by antibiotics and antibiotic-resistant bacteria must be placed as a worldwide health and ecological worry. Advanced oxidation processes (AOPs) are viewed as a greatly reasonable technique concerning water treatments for eliminating organic contaminants categorized as bio-recalcitrant and for the demobilization of pathogens, which are not touchable via traditional methods. This work discusses briefly the main recent facts and future trends in the field of applying AOPs in wastewater treatment. There is an urgent need for strengthening the studies on eliminating pollutants and microorganisms for wastewater reuse utilizing various AOPs. In-depth investigation about their reduction pathways employing AOPs is needed. Coupling AOPs with membrane processes should be kept in mind for better safety and pollutant removal.

Commercial TiO2 was impregnated with silver nanoparticles at 1 and 2 mol% Ag using a simple ‘liquid impregnation followed by heat treatment’ method and the material was characterized using field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM)/energy dispersive X-ray (EDX), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman, diffusive reflectance spectroscopy (DRS), and BET surface area/pore volume analysis. Impregnation of silver nanoparticles on P25 TiO2 was done using the same procedure. Commercial TiO2 was also modified under simple heat treatment to make combusted TiO2. To probe the challenge of photodegradation of a known carcinogen, malachite green (MG), we have investigated the UV-induced photodegradation of MG in aqueous medium using all these modified TiO2 catalysts in order to evaluate the effect of silver impregnation. We report that the presence of silver in TiO2 enhances the photon induced mineralization of MG but reduces the decolorization efficiency. Based on both decolorization and mineralization, and also on the cost and availability, 1% silver impregnated commercial TiO2 was found the optimal. The degradation of MG using this catalyst has been investigated in a more detail, and the effect of pH, stirring, initial MG concentration, catalyst dose, nature of light, and the presence of interfering ions/organics are examined. The dye (∼25 mg/l) is bleached almost completely upon 1 h of light irradiation under experimental conditions. The degradation follows zero-order kinetics over the entire MG concentration range (25–125 mg/l), and we presume that the degradation occurs via step-wise N-demethylation. Most importantly, we observe high turn over frequency (TOF) for our catalyst. This makes the catalytic process cost-effective and the catalyst recycle able. Further, a cost-analysis is made to evaluate the proper selection of the catalyst in terms of efficiency and economy.► Nano silver impregnation of commercial TiO2 and P25 TiO2. ► Modification of commercial TiO2 on heat treatment. ► Use of TiO2 based materials for photocatalytic degradation of malachite green (MG). ► Comparative performance evaluation of the catalysts. ► Effect of varying condition on MG degradation using Ag impregnated commercial TiO2.

The results, grouped in eight published research and divided into three blocks, are presented in Chapter IV and V:
A.- Biodegradation of surfactants
1.- Effect of concentration on the primary and ultimate biodegradation of alkylpolyglucosides in aerobic biodegradation test. This study examines the primary and ultimate biodegradation of a non-ionic surfactants, an alkylpolyglucoside, in ready biodegradability tests. The surfactant concentration was tested by the anthrone method, while the ultimate biodegradation (mineralization) was analyzed by the total organic carbon determinations. The influence of the concentration on the extent of primary and ultimate biodegradation and the kinetics of degradation also were determined. The primary and ultimate biodegradation was studied at different initial concentrations: 15, 25, 50, 75 y 100 mg/L. The increasing concentration of test chemical from 15 to 100 mg/L resulted in a decrease in the relative maximum mineralization rate and longer estimated lag times by a factor of approximately 4.3. During the degradative process, two different stages were noted; these are better described with Quiroga and first-order kinetic models, respectively. For the study of the influence of concentration, the parameters characteristics of the biodegradation profiles in the different biodegradation assays were evaluated.
2.- Environmental impact of ether carboxylic derivative surfactants. The ultimate aerobic biodegradability and toxicity of three ether carboxylic derivative surfactants having different alky chains and degrees of ethoxylation were investigated. Ultimate aerobic biodegradability was screened by means of dissolved organic carbon determinations at different initial surfactant concentrations. For comparison, the characteristics parameters of the biodegradation process, such as half-life, mean biodegradation rate, and residual surfactant concentration, were determined. Increased surfactant concentrations decreased mineralization and lengthened the estimated half-life. The results demonstrate that the ultimate aerobic biodegradability is higher for the surfactants with the shortest alkyl chain and highest degree of ethoxylation. Toxicity values of the surfactant, and their binary mixtures, were determined using three test organisms, the freshwater crustacean Daphnia magna, the luminescent bacterium Vibrio fischeri and the microalgae Selenastrum
capricornutum. The toxicity is lower for the surfactants with the shortest alkyl chain and highest degree of ethoxylation. The toxicity of binary mixtures of the three ether carboxylic surfactants at a 1:1 weight ratio was also measured. The least toxic mixture is formed by the surfactants having lower individual toxicity.
3.- Aerobic biodegradation of surfactant. In this work, biodegradation of several families of surfactants was studied. The test used were: screening test, confirmatory test, respirometry test and the biodegradation test with Pseudomonas putida. According to the analysis, the biodegradation results depend on the biodegradation test used and the surfactant structure. The importance of the influence of the initial concentration has been evidenced. All the surfactant tested can be considered as biodegradable at low concentrations. Fatty-alcohol ethoxylates and especially the FAE-R12-14E11 are the most biodegradable, but the alkyl eter carboxylic acid derivative surfactants are the least biodegradable.
B.- Toxicity of surfactants
4.- Ecotoxicity of anionic surfactants AKYPO®. In this paper, toxicity values of ether carboxylic derivatives surfactants with commercial name AKYPO®, and the anionic surfactant linear alkylbenzene sulfonate (LAS), have been determined by applying the 24-h immobilization test with Daphnia magna (freshwater crustacea), the LumiStox® 300 test which employs the luminescent bacterium Photobacterium phosphoreum of the strain Vibrio fischeri, and the 72-h algal growth-inhibition test with the microalgae Selenastrum capricornutum, using culture-growth inhibition as the effect criterion. Three ether carboxylic derivatives surfactants with different alkyl chain and degree of ethoxylation (EC-R8E8, EC-R12-14E3, EC-R12-14E10), and LAS have been tested. For all tests, the results indicated that Vibrio fischeri is more sensitive to toxic effects from ether carboxylic derivatives surfactants and LAS than Daphnia magna or Selenastrum capricornutum. The results demonstrate that the toxicity is lower for the ether carboxylic derivatives surfactants with the shortest alkyl chain. The anionic surfactant LAS presents intermediate toxicity values.
5.- Acute toxicity of alkylpolyglucosides to Vibrio fischeri, Daphnia magna and microalgae: a comparative study. In this work, toxicity values of alkylpolyglucosides have been determined by applying the 24-h immobilization test with Daphnia magna, the LumiStox 300 test which employs the luminescent bacteria Vibrio fischeri and the test with Selenastrum capricornutum. Three alkylpolyglucosides with different alkyl chain and degree of polymerisation have been tested. For all tests, the results indicated that V. fischeri was more sensitive to toxic effects from alkylpolyglucosides than was D. magna or S. capricornutum. The results demonstrate considerable variation in toxicity responses within structurally related glucose-based surfactants regardless of the species tested. The toxicity increased as the critical micelle concentration decreased, and as the alkyl chain length and resultant hydrophobicity increased.
C.- Ozonization of surfactants
6.- Influence of ozonation processes on the microbial degradation of surfactants. The influence of ozonation of aqueous solutions of non-ionic surfactants was investigated in this study. The research was conducted using solutions of amine oxide based surfactants. These surfactants constitute a particular class of non-ionic surfactants that exhibit cationic behaviour in acid solution, they show good foaming properties and are skin compatible. The ozonation process was carried out at 25ºC in a stirred tank reactor for 30 min, where gaseous ozone was bubbled. The degree of mineralization achieved after the ozonation process was evaluated by measuring the total organic carbon before and after ozonation.
The influence of ozonation on biodegradability of the solutions was studied using the biodegradation test by Pseudomonas putida. Biodegradation efficiency of the ozonated amine oxides based surfactants was also evaluated. It was found that the effectiveness of ozonation depended on the chemical structure of surfactant molecule. Ozonation only slightly improved biodegradation of these surfactants.
7.- Combined use of ozonation and biodegradation of anionic and non-ionic surfactants. This study investigated the extent of primary and final biodegradation of anionic and non-ionic surfactants to evaluate the combined use of ozonation and biodegradation in surfactant removal. The surfactants used were alkylpolyglucosides and linear alkyl benzene sulfonates. The anionic surfactant containing a benzene ring on its structure was oxidized faster than was the non-ionic surfactant. Both surfactants showed poor mineralization due to ozonation indicating an ozone attack primarily on carbon bonds. The results indicate that the removal of surfactants and of the total organic carbon is increased by the consecutive use of ozonation and biodegradation.
8.- Ozonation of anionic and non-ionic surfactants in aqueous solutions: impact on aquatic toxicity. The objective of this study was to investigate the influence of ozonation of anionic and non-ionic surfactants on their aquatic toxicity. Toxicity values of various commercially important anionic and non-ionic surfactants have been determined using the luminescent bacterium Vibrio fischeri. Surface tension measurements were made to study the interfacial activity. The behavior depends on the chemical structure. Some intermediate ozonation products were found to be more toxic than the base surfactant and others were found to be less. Surfactants with aromatic rings such as linear alkyl benzene sulfonates, or surfactants with glycosidic groups such as alkylpolyglucosides, exhibit a lower toxicity after ozonation. On the other hand, ether groups present in the fatty-alcohol ethoxylates and ether carboxylic derivative surfactants, and carboxylic acid derivatives present in the ether carboxylic derivative surfactants lead to increasing toxicity after ozonation. Surfactants with ether groups probably formed short-chain polyethoxylated compounds and carboxylic acids, which are possibly responsible for the surface-tension decrease that promotes the toxicity increase.
GENERAL CONCLUSIONS
Finally, the main conclusions from the various research are presented in Chapter VI.

Methylene Blue dye is an aromatic chemical compound with a molecular formula C16H18N3SCl and has some very distinctive uses in some fields like biology and chemistry.  Its uses are diverse as they can be used in paper and pulp industries, leather industries and can also be used for medicinal purposes.  This paper focuses on the degradation of methylene blue using Fenton and Oxidative processes and how to remove this dye compound from water solution.  The material used, its environmental effect, advantages and recommendations are also discussed.

To reduce the pollutants from the effluent heterogeneous photocatalysis process is the environment friendly process. In degrading bio-recalcitrant compounds the photocatalytic process has proved to be superior to various conventional treatment processes. During the photocatalytic degradation, the transfer of hazardous contaminants from one form to another do not takes place and complete degradation of contaminants takes place. Due to the use of Artificial UV light and Semiconductor as a catalyst, this process is quite. The application of Photocatalytic process at industrial scale is possible in India. So Photocatalysis is attractive and cost-effective option in our country. With varying parameters like pH, irradiation time, catalyst dose and UV light intensity the degradation process is studied. Under the optimum pH of the solution (7.0 pH), catalyst dose of 1.2 g/500ml after 6 hr conditions 97%, 90% and 83% degradation in BOD, COD & Colour was observed.

The protection and conservation of natural resources is one of the main priorities of modern society. Water is perhaps our most valuable resource, and thus should be recycled. Many of the current recycling techniques for polluted water only concentrate the pollutant without degrading it or eliminating it. In this sense, advanced oxidation processes are possibly one of the most effective methods for the treatment of wastewater containing organic products (effluents from chemical and agrochemical industries, the textile industry, paints, dyes, etc.). More conventional techniques cannot be used to treat such compounds because of their high chemical stability and/or low biodegradability. This article describes, classifies, and analyzes different types of advanced oxidation processes and their application to the treatment of polluted wastewater.

A strategy for adaptive control and energetic optimization of aerobic fermentors was implemented, with both air flow and agitation speed as manipulated variables. This strategy is separable in its components: control, optimization, estimation. We optimized parameter’s estimation (from the usual KLa correlation) using sinusoidal excitation of air flow and agitation speed. We have implemented parameter’s estimation trough recursive least squares algorithm with forgetting factor. We carried separate essays on control, optimization and estimation algorithms. We carried our essays using an original computational simulation environment, with noise and delay generating facilities for data sampling and filtering.

Our results show the convergence and robustness of the estimation algorithm used, improved with use of both forgetting factor and KLa dead-band facilities. Control algorithm used in our work compares favorably with PID using the integrated area criteria for deviation between oxygen molarity and critical molarity (set point). Optimization algorithm clearly reduces energetic consumption, respecting critical molarity. Integration of control, optimization and adaptive algorithms was implemented, but future work is needed for stability. Methods were defined and implemented for stability improvement. We have implemented data acquisition and computer manipulation of air flow and agitation speed for actual fermentors.

In this experiment the removal of printing dyes from textile printing industry effluents was carried out by Advanced Oxidation Process (AOP) in which heterogeneous photocatalytic treatment of textile printing wastewater using UV/H2O2/TiO2 system was studied. For the treatment of textile effluents different concentration of titanium dioxide (TiO2) and effect of application time of UV radiation was investigated. The degradation of treated wastewater was estimated spectrophotometrically. To check the extent of mineralization and decolorization after treatment water quality parameter such as percentage degradation, COD, BOD, TOC, pH, DO and toxicity were studied. Before treatment the values of water quality parameters were as; COD (1950 mg/L), BOD (963 mg/L), TOC (3410 mg/L), pH (9.6) and DO (1.77 mg/L). After application of UV/H2O2/TiO2 degradation was observed to be 72% and reduction in COD, BOD, TOC were 58%, 57%, 48%, and increase in DO level was up to 49% respectively. For the eval...

Deforestation in several countries has led to the crumbling and disintegration of forest with high effects of vulnerability on forest habitat, vegetation structures and extinction of wild life. Unfortunately deforestation affects the sustainability of the environment on a global scale with more detrimental effects on developing countries.  Consequences of deforestation include global warming, flooding, climate change, water and air pollution. Removal of trees without proper replacement with new ones threatens human live which can lead to poverty. Findings reveal that at least 70% of the developing world lives below poverty line. This paper talks about deforestation on a global scale, how it affects human life, its benefits and how we should join hands with the relevant authorities to stop the damages done to the environment by cutting down trees.

Dechlorination and denitration are known to occur during the oxidative degradation of chloronitroaromatic compounds, but the possibility of re-chlorination and re-nitration of chloro and nitro groups is not assessed despite of its importance in evaluating the applicability of advanced oxidation processes (AOPs). In this study, transformation of chloro and nitro groups in degradation of 4-chloro-2-nitrophenol (4C2NP) by sulfate radical generated via Co-mediated peroxymonosulfate activation was investigated. Both chloride and nitrate ions were found as the main inorganic products of chloro and nitro groups in 4C2NP, but their levels were much lower than that of degraded parent 4C2NP. A typical dual effect of chloride on the 4C2NP degradation kinetics was observed, whereas no measurable influence was found for addition of low level nitrate. Re-chlorination took place, but re-nitration was not verified because several polychlorophenols but none of polynitrophenols were detected. The specific degradation mechanism involved in the transformation of nitro group and chloro group was proposed.

Environmental and health concerns have resulted in significant activities to find substitutes for lead-contained solders for microelectronics. The potential candidates such as Sn-Ag1 and Sn-Ag-Cu1 eutectic solders with melting temperatures of 221°C and 217°C, respectively are the most prominent solders because of their excellent mechanical properties as compared with that of eutectic Sn-Pb solder2. Other candidates as drop in replacements for eutectic Pb-Sn solder, such as Sn-In-Zn alloys, may have melting point close to 185°C, though not eutectic, and an acceptable solidification range but have received only limited attention due to various reasons & concerns1. In semiconductor packaging industry, lead-free solders such as Sn-Ag1 and Sn-Ag-Cu1 have been widely applied in mass production of ball grid array products. Such alloys are often used for C5 solder system. However, one of the major challenges is oxidation after thermal processing such as reflow, burn-in, data retention bake and hot temperature testing. A study was conducted on BGA lead-free C5 solder joint system to assess the effect of Germanium (Ge) addition to Sn3.5Ag and Sn3.8Ag0.7Cu solder alloy. The main objective of this study is to find a way to resolve solder surface oxidation after thermal processes, while determining if there's any adverse effect on the solder joint by Ge addition. Experimental works were carried out to observe the melting properties and solder surface morphology by Differential Scanning Calorimetry (DSC) and SEM. Solder surface oxidation was measured by EDX. Shear and pull strength was measured by Dage which is representative of the intermetallic (IMC) strength between the C5 solder sphere and Cu/Ni/Au pad finishing. Solderability test was conducted per Jedec standard. Tray and Packaging Drop Tests were done to gauge solder joint performance against impact force. A comprehensive study was done to study the effect of microstructure and interface intermetallic of both solder system at ambient, high temperature storage (HTS) at 150°C for 24, 48, 96, 168, 504 and 2000 hours and multiple reflow of 1x, 2x, 3x, 6x towards the joint integrity. Overall, Ge doped alloys had significantly higher ball shear and ball pull strength. EPMA microstructure analysis after cross-sectioning on bulk solder and IMC revealed traces of Ge that contributed to the significant increase in ball shear and ball pull strength, while did not cause any bulk solder and IMC morphology changes. Solderability test passed. Drop tests had comparable performance as non Ge doped alloys. In conclusion, addition of Ge in Sn3.5Ag and Sn3.8Ag0.7Cu lead-free solder alloys is able to resolve surface oxidation problem after thermal processing, with improvement in solder joint strength for overall lead-free package robustness.

http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=5416568&tag=1

Purpose: The review article discusses the title topic describing mostly the authors work on green chemical,  photochemical and electrochemical methods for the treatment of organic wastes present in different matrices.  Emphasis is mainly placed on the importance of the matrix, associated compounds and the method's selection. Methodology: Different green methods of treatment for organic waste available are reviewed with an outline of scientific principles. Different case studies, from the authors, work, involving the treatment of organic waste present in different matrices are discussed.  Available green chemical,  photochemical, and electrochemical methods are reviewed, and the results obtained are described and discussed. The rationale behind the choice of method was discussed in detail. Laboratory to plant adoption and the considerations therein are considered.
Main findings: The selection of treatment method depends on the nature of the organic waste and the matrix in which it is present.  This has been brought out in the study.  Advanced oxidation and electrochemical oxidation processes are practically useful methods for waste treatment and are discussed with case studies. The optimization of the advanced oxidation process is still an empirical approach. It needs a sound scientific base.
Applications of the work: The case studies described in the paper enable the proper choice of treatment method among several available options.  The study covers the essential green chemical techniques,  viz.,  photochemical and electrochemical techniques.
The novelty of the work: Many of the organic substrates subjected to treatment study were rarely reported in the open literature. Laboratory to plant scale development and the factors involved therein have been brought in many places.

This paper comes out from the need to provide an improvement in the current oil refinery wastewater treatment plant (WWTP) aiming to generate water for reuse. The waste-water was pretreated and collected in the WWTP after the biological treatment unit (bio-disks) followed by sand filtration. Ozonation (ozone concentration from 3.0– 60 mgO 3 L −1), UV (power lamp from 15 to 95 W), H 2 O 2 (carbon:H 2 O 2 molar ratio of 1:1, 1:2, and 1:4), and two advanced oxidation processes (UV/O 3 and UV/H 2 O 2) were investigated aiming to reduce the wastewater organic matter and generate water with suitable characteristics for the reverse osmosis operation and subsequent industrial reuse. Even after the biological and filtration treatments, the oil refinery waste-water still presented an appreciable amount of recalcitrant organic matter (TOC of 12–19 mgC L −1) and silt density index (SDI) higher than 4, which is considered high for subsequent reverse osmosis due to membrane fouling risks. Experiments using non combined processes (O 3 , H 2 O 2 , and UV only) showed a low degree of mineralization after 60 min of reaction , although the pretreatment with ozone had promoted the oxidation of aromatic compounds originally found in the real matrix, which suggests the formation of recalcitrant compounds. When the combined processes were applied, a considerable increase in the TOC removal was observed (max of 95 % for UV/O 3 process, 55 W, 60 mgO 3 L −1), likely due the presence of higher amounts of reactive species, specially hy-droxyl radicals, confirming the important role of these species on the photochemical degradation of the wastewater compounds. A zero-order kinetic model was fitted to the experimental data and the rate constant values (k, mgC L −1 h −1) ranged from 4.8 < k UV/O3 < 11 ([O 3 ] 0 = 30–60 mg L −1), and 8.6 < k UV/H2O2 < 11 (C:H 2 O 2 from 1:1 to 1:4). The minimum and maximum electrical energy per order (E EO) required for 60 min of treatment were calculated as 5.4 and 81 Wh L −1 , respectively, for UV/O 3 (15 W, 60 mgO 3 L −1) and UV/H 2 O 2 (95 W, 1C:1H 2 O 2). Good results in terms of water conditioning for reverse osmosis operation were obtained using UV/ H 2 O 2 process with initial molar ratio of 1 C:2 H 2 O 2 (UV lamp 55 W) and 1 C:4 H 2 O 2 (UV lamp 95 W), and total organic carbon (TOC) removals of 62 % (SDI 15 = 1.8) and 74 % (SDI 15 = 2.0) were achieved, respectively, after 60 min. The treated wastewater followed to the reverse osmosis system, which operated with an adequate flux of permeate, was very efficient to remove salt and generate a permeate water with the required quality for industrial reuse.

The treatment of high-strength petroleum refinery effluent (PRE) with [BOD5]/[COD](0) = 0.14 was investigated using combined Fenton-sequencing batch reactor (SBR). The effect of [H2O2]:[COD](0) molar ratio on biodegradability enhancement was investigated. Fenton optimal conditions were: [H2O2]:[COD](0) of 6, [H2O2]:[Fe-0] of 10 and pH = 3.0 that could remove 76.5%, 45% and 96% of COD, TOC and phenol and increased biodegradability ratio to 0.37. The pretreated PRE subjected to SBR for one single cycle of 10 h. The results revealed the effectiveness of hybrid Fenton-SBR system in treating PRE where the complete treatment of the PRE was attained by this system. (C) 2014 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.

Link to full text articles :
http://www.sciencedirect.com/science/article/pii/S1226086X1400522X 
http://ac.els-cdn.com/S1226086X1400522X/1-s2.0-S1226086X1400522X-main.pdf?_tid=4d49b94a-4011-11e5-b09d-00000aab0f01&acdnat=1439288056_0daf270234cb91a5c805cd234e5478be

This paper presents the results of experimental and theoretical investigations of the process of nonthermal plasma-assisted reforming of aqueous ethanol solutions in the dynamic plasma-liquid system based on the electric discharge in a gas channel with liquid wall. The experiments show possibilities and efficiency of low-temperature plasma-chemical conversion of liquid ethanol into synthesis gas. The numerical modeling clarifies the nature and explains the kinetic mechanism of nonequilibrium plasma-chemical transformations in the system.