- Hiroshima University, Department of Civil Engineering, Faculty MemberShanghai Jiao Tong University, Environmental Engineering, Post-Doc, and 2 moreadd
- My research expertise covers water/wastewater treatment with using different physical, chemical and biological methods.edit
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Per- and polyfluoroalkyl substances (PFAS), one of the main categories of emerging contaminants, are a family of fluorinated organic compounds of anthropogenic origin. PFAS can endanger the environment and human health because of their... more
Per- and polyfluoroalkyl substances (PFAS), one of the main categories of emerging contaminants, are a family of fluorinated organic compounds of anthropogenic origin. PFAS can endanger the environment and human health because of their wide application in industries, long-term persistence, unique properties, and bioaccumulation potential. This study sought to explain the accumulation of different PFAS in water bodies. In aquatic environments, PFAS concentrations range extensively from <0.03 (groundwater; Melbourne, Australia) to 51,000 ng/L (Groundwater, Sweden). Additionally, bioaccumulation of PFAS in fish and water biota has been stated to range from 0.2 (Burbot, Lake Vättern, Sweden) to 13,900 ng/g (Bluegill samples, U.S.). Recently, studies have focused on PFAS removal from aqueous solutions; one promising technique is advanced oxidation processes (AOPs), including microwaves, ultrasound, ozonation, photocatalysis, UV, electrochemical oxidation, the Fenton process, and hydrogen peroxide-based and sulfate radical-based systems. The removal efficiency of PFAS ranges from 3% (for MW) to 100% for UV/sulfate radical as a hybrid reactor. Therefore, a hybrid reactor can be used to efficiently degrade and remove PFAS. Developing novel, efficient, cost-effective, and sustainable AOPs for PFAS degradation in water treatment systems is a critical area of research.
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The presence of dyes in aquatic environments can have harmful effects on aquatic life, including inhibiting photosynthesis, decreasing dissolved oxygen levels, and altering the behavior and reproductive patterns of aquatic organisms. In... more
The presence of dyes in aquatic environments can have harmful effects on aquatic life, including inhibiting photosynthesis, decreasing dissolved oxygen levels, and altering the behavior and reproductive patterns of aquatic organisms. In the initial phase of this review study, our aim was to examine the categories and properties of dyes as well as the impact of their toxicity on aquatic environments. Azo, phthalocyanine, and xanthene are among the most frequently utilized dyes, almost 70–80% of used dyes, in industrial processes and have been identified as some of the most commonly occurring dyes in water bodies. Apart from that, the toxicity effects of dyes on aquatic ecosystems were discussed. Toxicity testing relies heavily on two key measures: the LC50 (half-lethal concentration) and EC50 (half-maximal effective concentration). In a recent study, microalgae exposed to Congo Red displayed a minimum EC50 of 4.8 mg/L, while fish exposed to Disperse Yellow 7 exhibited a minimum LC50 of 0.01 mg/L. Anaerobic membrane bioreactors (AnMBRs) are a promising method for removing dyes from water bodies. In the second stage of the study, the effectiveness of different AnMBRs in removing dyes was evaluated. Hybrid AnMBRs and AnMBRs with innovative designs have shown the capacity to eliminate dyes completely, reaching up to 100%. Proteobacteria, Firmicutes, and Bacteroidetes were found to be the dominant bacterial phyla in AnMBRs applied for dye treatment. However, fouling has been identified as a significant drawback of AnMBRs, and innovative designs and techniques are required to address this issue in the future.
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The potential of microalgal photobioreactors in removing total ammonia nitrogen (TAN), chemical oxygen demand (COD), caffeine (CAF), and N,N-diethyl-m-toluamide (DEET) from synthetic wastewater was studied. Chlorella vulgaris achieved... more
The potential of microalgal photobioreactors in removing total ammonia nitrogen (TAN), chemical oxygen demand (COD), caffeine (CAF), and N,N-diethyl-m-toluamide (DEET) from synthetic wastewater was studied. Chlorella vulgaris achieved maximum removal of 62.2% TAN, 52.8% COD, 62.7% CAF, and 51.8% DEET. By mixing C. vulgaris with activated sludge, the photobioreactor showed better performance, removing 82.3% TAN, 67.7% COD, 85.7% CAF, and 73.3% DEET. Proteobacteria, Bacteroidetes, and Chloroflexi were identified as the dominant phyla in the activated sludge. The processes were then optimized by the artificial neural network (ANN). High R2 values (>0.99) and low mean squared errors demonstrated that ANN could optimize the reactors’ performance. The toxicity testing showed that high concentrations of contaminants (>10 mg/L) and long contact time (>48 h) reduced the chlorophyll and protein contents in microalgae. Overall, a green technology for wastewater treatment using microalgae and bacteria consortium has demonstrated its high potentials in sustainable management of water resources.
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This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
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The consumption of pharmaceuticals and personal care products (PPCPs) has been widely increasing, yet up to 90–95% of PPCPs consumed by human are excreted unmetabolized. Moreover, the most of PPCPs cannot be fully removed by wastewater... more
The consumption of pharmaceuticals and personal care products (PPCPs) has been widely increasing, yet up to 90–95% of PPCPs consumed by human are excreted unmetabolized. Moreover, the most of PPCPs cannot be fully removed by wastewater treatment plants (WWTPs), which release PPCPs to natural water bodies, affecting aquatic ecosystems and potentially humans. This study sought to review the occurrence of PPCPs in natural water bodies globally, and assess the effects of important factors on the fluxes of pollutants into receiving waterways. The highest ibuprofen concentration (3738 ng/L) in tap water was reported in Nigeria, and the highest naproxen concentration (37,700 ng/L) was reported in groundwater wells in Penn State, USA. Moreover, the PPCPs have affected aquatic organisms such as fish. For instance, up to 24.4 × 103 ng/g of atenolol was detected in P. lineatus. Amongst different technologies to eliminate PPCPs, algae-based systems are environmentally friendly and effective because of the photosynthetic ability of algae to absorb CO2 and their flexibility to grow in different wastewater. Up to 99% of triclosan and less than 10% of trimethoprim were removed by Nannochloris sp., green algae. Moreover, variable concentrations of PPCPs might adversely affect the growth and production of algae. The exposure of algae to high concentrations of PPCPs can reduce the content of chlorophyll and protein due to producing reactive oxygen species (ROS), and affecting expression of some genes in chlorophyll (rbcL, psbA, psaB and psbc).
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Anaerobic ammonia oxidation (anammox) is an environmentally friendly, cost-effective, and biological method for nitrogen treatment from aqueous solutions. However, slow growth rate, negative effects of high concentration of nitrite,... more
Anaerobic ammonia oxidation (anammox) is an environmentally friendly, cost-effective, and biological method for nitrogen treatment from aqueous solutions. However, slow growth rate, negative effects of high concentration of nitrite, ammonia and other pollutants (such as metals) on anammox activity are the main drawbacks of using anammox. Thus, in this study, anammox was attached on chitosan to improve anam- mox performance. Two reactors comprising chitosan and anammox bacteria (first reactor, chitosan/anam- mox) and solely anammox (second reactor, control) were run for 73 d. The nitrogen loading rate (NLR) var- ied from 2 to 14 gN/(L d), while the nitrogen concentration varied from 80 to 700 mg/L. The chitosan/ anammox reactor showed a better performance than the sole anammox (control), with respective maxi- mum abatement values of ammonia (NH4+), nitrite (NO2-), and total nitrogen (TN) of 90.8%, 83.5%, and 81.7% on days 20–25 under a NLR of 8–10 kgTN/(m3 d). Response surface methodology (RSM) was em- ployed to optimize the performance of both reactors, and a reasonable R2 value showed that the RSM well optimized the performance of the reactors. After Xnding the optimum performance conditions for both re- actors, Fe and Cu (0.5–7.0 mg/L) were added to the inYuent to monitor the effects of metals on the perfor- mance of both reactors. The performance of both reactors decreased to 0% following the addition of 7.0 (first reactor) and 6.5 (second reactor) mg/L Cu and Fe, respectively. This indicated that chitosan not only enhanced nitrogen removal by anammox but also improved the resistance of anammox to metals.
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Landfill leachate is characterised by high chemical and biological oxygen demand and generally consists of undesirable substances such as organic and inorganic contaminants. Landfill leachate may differ depending on the content and age of... more
Landfill leachate is characterised by high chemical and biological oxygen demand and generally consists of undesirable substances such as organic and inorganic contaminants. Landfill leachate may differ depending on the content and age of landfill contents, the degradation procedure, climate and hydrological conditions. We aimed to explain the characteristics of landfill leachate and define the practicality of using different techniques for treating landfill leachate. Different treatments comprising biological methods (e.g. bioreactors, bioremediation and phytoremediation) and physicochemical approaches (e.g. advanced oxidation processes, adsorption, coagulation/ flocculation and membrane filtration) were investigated in this study. Membrane bioreactors and integrated biological techniques, including integrated anaerobic ammonium oxidation and nitrification/denitrification processes, have demonstrated high performance in ammonia and nitrogen elimination, with a removal effectiveness of more than 90%. Moreover, improved elimination efficiency for suspended solids and turbidity has been achieved by coagulation/ flocculation techniques. In addition, improved elimination of metals can be attained by combining different treatment techniques, with a removal effectiveness of 40-100%. Furthermore, combined treatment techniques for treating landfill leachate, owing to its high chemical oxygen demand and concentrations of ammonia and low biodegradability, have been reported with good performance. However, further study is necessary to enhance treatment methods to achieve maximum removal efficiency.
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Antibiotics are frequently applied to treat bacterial infections in humans and animals. However, most consumed antibiotics are excreted into wastewater as metabolites or in their original form. Therefore, removal of antibiotics from... more
Antibiotics are frequently applied to treat bacterial infections in humans and animals. However, most consumed antibiotics are excreted into wastewater as metabolites or in their original form. Therefore, removal of antibiotics from aquatic environments is of high research interest. In this study, we investigated the removal of sulfamethoxazole (SMX) and ofloxacin (OFX) with Chae-toceros muelleri, a marine diatom. The optimization process was conducted using response surface methodology (RSM) with two independent parameters, i.e., the initial concentration of antibiotics and contact time. The optimum removal of SMX and OFX were 39.8% (0.19 mg L −1) and 42.5% (0.21 mg L −1) at the initial concentration (0.5 mg L −1) and contact time (6.3 days). Apart from that, the toxicity effect of antibiotics on the diatom was monitored in different SMX and OFX concentrations (0 to 50 mg L −1). The protein (mg L −1) and carotenoid (µg L −1) content increased when the antibiotic concentration increased up to 20 mg L −1 , while cell viability was not significantly affected up to 20 mg L −1 of antibiotic concentration. Protein content, carotenoid, and cell viability decreased during high antibiotic concentrations (more than 20 to 30 mg L −1). This study revealed that the use of Chae-toceros muelleri is an appealing solution to remove certain antibiotics from wastewater.
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Using microalgae to remove pharmaceuticals and personal care products (PPCPs) mi-cropollutants (MPs) has attracted considerable interest. However, high concentrations of persistent PPCPs can reduce the performance of microalgae in... more
Using microalgae to remove pharmaceuticals and personal care products (PPCPs) mi-cropollutants (MPs) has attracted considerable interest. However, high concentrations of persistent PPCPs can reduce the performance of microalgae in remediating PPCPs. Three persistent PPCPs, namely, carbamazepine (CBZ), sulfamethazine (SMT) and tramadol (TRA), were treated with a combination of Chaetoceros muelleri and biochar in a photobioreactor during this study. Two reactors were run. The first reactor comprised Chaetoceros muelleri, as the control, and the second reactor comprised Chaetoceros muelleri and biochar. The second reactor showed a better performance in removing PPCPs. Through the response surface methodology, 68.9% (0.330 mg L −1) of CBZ, 64.8% (0.311 mg L −1) of SMT and 69.3% (0.332 mg L −1) of TRA were removed at the initial concentrations of MPs (0.48 mg L −1) and contact time of 8.1 days. An artificial neural network was used in optimis-ing elimination efficiency for each MP. The rational mean squared errors and high R 2 values showed that the removal of PPCPs was optimised. Moreover, the effects of PPCPs concentration (0-100 mg L −1) on Chaetoceros muelleri were studied. Low PPCP concentrations (<40 mg L −1) increased the amounts of chlorophyll and proteins in the microalgae. However, cell viability, chlorophyll and protein contents dramatically decreased with increasing PPCPs concentrations (>40 mg L −1).
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Occurrence of pharmaceutical micropollutants in aquatic environments has been one amongst serious environmental problems. During this study, two reactors, including a sequencing batch reactor (SBR) + powdered composite adsorbent (CA)... more
Occurrence of pharmaceutical micropollutants in aquatic environments has been one amongst serious environmental problems. During this study, two reactors, including a sequencing batch reactor (SBR) + powdered composite adsorbent (CA) (first reactor, SBR + CA) and a sequencing batch reactor (second reactor, SBR), were designed to treat synthetic wastewater. Powdered CA was added with a dosage of 4.8 g L−1 to the first reactor. Tap water was contaminated with chemical oxygen demand (COD), ammonia and three pharmaceuticals, namely, atenolol (ATN), ciprofloxacin (CIP) and diazepam (DIA) to produce synthetic wastewater. The SBR + CA illustrated a better performance during synthetic municipal wastewater treatment. Up to 138.6 mg L−1 (92.4%) of COD and up to 114.2 mg L−1 (95.2%) of ammonia were removed by the first reactor. Moreover, optimisation of pharmaceuticals removal was conducted through response surface methodology (RSM) and artificial neural network (ANN). Based on the RSM, the best elimination of ATN (90.2%, 2.26 mg L−1), CIP (94.0%, 2.35 mg L−1) and DIA (95.5%, 2.39 mg L−1) was detected at the optimum initial concentration of MPs (2.51 mg L−1) and the contact time (15.8 h). In addition, ANN represented a high R2 value (>0.99) and a rational mean squared error (<1.0) during the optimisation of micropollutants removal by both reactors. Moreover, adsorption isotherm study showed that the Freundlich isotherm could justify the abatement of micropollutants by using CA better than the Langmuir isotherm.
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In this study, hexadecylamine (HDA) impregnated chitosan-powder activated carbon (Ct-PAC) composite beads were successfully prepared and applied to adsorption of the anionic dye reactive black 5 (RB5) in aqueous solution. The Ct-PAC-HDA... more
In this study, hexadecylamine (HDA) impregnated chitosan-powder activated carbon (Ct-PAC) composite beads were successfully prepared and applied to adsorption of the anionic dye reactive black 5 (RB5) in aqueous solution. The Ct-PAC-HDA beads synthesized with 0.2 g powdered activated carbon (PAC) and 0.04 g HDA showed the highest dye removal efficiency. The prepared beads were characterized using Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Various adsorption parameters, i.e., adsorbent dosage, pH, and contact time, which affect the adsorption performance, were studied in a series of batch experiments. The obtained adsorption data were found to be better represented by Freundlich (R 2 = 0.994) and pseudo-second-order (R 2 = 0.994) models. Moreover, it was ascertained that the adsorption of RB5 onto Ct-PAC-HDA beads is pH-dependent, and the maximum Langmuir adsorption capacity (666.97 mg/g) was observed at pH 4. It was also proved that Ct-PAC-HDA beads were regenerable for repeated use in the adsorption process.
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Although pesticides are widely used in agriculture, industry and households, they pose a risk to human health and ecosystems. Based on target organisms, the main types of pesticides are herbicides, insecticides and fungicides , of which... more
Although pesticides are widely used in agriculture, industry and households, they pose a risk to human health and ecosystems. Based on target organisms, the main types of pesticides are herbicides, insecticides and fungicides , of which herbicides accounted for 46% of the total pesticide usage worldwide. The movement of pesticides into water bodies occurs through runoff , spray drift, leaching, and sub-surface drainage, all of which have negative impacts on aquatic environments and humans. We sought to define the critical factors affecting the fluxes of contaminants into receiving waters. We also aimed to specify the feasibility of using sorbents to remove pesticides from waterways. In Karun River in Iran (1.21 × 10 5 ng/L), pesticide concentrations are above regulatory limits. The concentration of pesticides in fish can reach 26.1 × 10 3 μg/kg, specifically methoxychlor herbicide in Perca fluviatilis in Lithuania. During the last years, research has focused on elimination of organic pollutants, such as pesticides, from aqueous solution. Pesticide adsorption onto low-cost materials can effectively remediate contaminated waters. In particular, nanoparticle adsorbents and carbon-based adsorbents exhibit high performance (nearly 100%) in removing pesticides from water bodies.
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Cadmium is a toxic heavy metal that may be detected in soils and plants. Wheat, as a food consumed by 60% of the world's population, may uptake a high quantity of Cd through its roots and translocate Cd to the shoots and grains thus... more
Cadmium is a toxic heavy metal that may be detected in soils and plants. Wheat, as a food consumed by 60% of the world's population, may uptake a high quantity of Cd through its roots and translocate Cd to the shoots and grains thus posing risks to human health. Therefore, we tried to explore the journey of Cd in wheat via a review of several papers. Cadmium may reach the root cells by some transporters (such as zinc-regulated transporter/iron-regulated transporter-like protein, low-affinity calcium transporters, and natural resistance-associated macrophages), and some cation channels or Cd chelates via yellow stripe 1-like proteins. In addition, some of the effective factors regarding Cd uptake into wheat, such as pH, organic matter, cation exchange capacity (CEC), Fe and Mn oxide content, and soil texture (clay content), were investigated in this paper. Increasing Fe and Mn oxide content and clay minerals may decrease the Cd uptake by plants, whereas reducing pH and CEC may increase it. In addition, the feasibility of methods to diminish Cd accumulation in wheat was studied. Amongst agronomic approaches for decreasing the uptake of Cd by wheat, using organic amendments is most effective. Using biochar might reduce the Cd accumulation in wheat grains by up to 97.8%.
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Rice consumption is a source of arsenic (As) exposure, which poses serious health risks. In this study, the accumulation of As in rice was studied. Research shows that As accumulation in rice in Taiwan and Bangladesh is higher than that... more
Rice consumption is a source of arsenic (As) exposure, which poses serious health risks. In this study, the accumulation of As in rice was studied. Research shows that As accumulation in rice in Taiwan and Bangladesh is higher than that in other countries. In addition, the critical factors influencing the uptake of As into rice crops are defined. Furthermore, determining the feasibility of using effective ways to reduce the accumulation of As in rice was studied. AsV and AsIII are transported to the root through phosphate transporters and nodulin 26-like intrinsic channels. The silicic acid transporter may have a vital role in the entry of methylated As, dimethylarsinic acid (DMA) and monomethylarsonic acid (MMA), into the root. Amongst As species, DMA(V) is particularly mobile in plants and can easily transfer from root to shoot. The OsPTR7 gene has a key role in moving DMA in the xylem or phloem. Soil properties can affect the uptake of As by plants. An increase in organic matter and in the concentrations of sulphur, iron, and manganese reduces the uptake of As by plants. Amongst the agronomic strategies in diminishing the uptake and accumulation of As in rice, using microalgae and bacteria is the most efficient.
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Recently, anammox bacteria have been applied for nitrogen elimination from wastewater. However, anammox is not effective for other kinds of pollutants. Therefore, in this study, the treatment of synthetic wastewater via combining anammox... more
Recently, anammox bacteria have been applied for nitrogen elimination from wastewater. However, anammox is not effective for other kinds of pollutants. Therefore, in this study, the treatment of synthetic wastewater via combining anammox and biochar in a fixed-bed column was considered to improve performance. Two reactors, Reactor 1 (containing biochar and anammox bacteria) and Reactor 2 (containing biochar as a control), were run for four months. The nitrogen concentration (mg/L) and nitrogen loading rate (g-N/L/day) ranged from 100 to 500 and 5 to 20, respectively. Reactor 1 showed better performance in removing nitrogen from wastewater than Reactor 2. For Reactor 1, the optimum nitrogen removal effectiveness and nitrogen removal rate (g/L/day) were 82.3% and 8.2 (phase 1, 0–29 days), 90.9% and 12.7 (phase 2, 30–59 days), 72.3% and 13.0 (phase 3, 60–89 days), and 69.5% and 6.9 (phase 4, 90–119 days), respectively. An artificial neural network was applied for optimization. After finding the optimum performance conditions for the Reactor 1, COD (200 mg/L to 500 mg/L) was added to the influent. Adding up to 275 mg/L COD did not significantly affect N elimination, but after this point, N elimination was dramatically decreased.
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Among countless applications, chitosan has the potential to be an effective and cheap adsorbent for pollutant removal in (waste) water. In form of beads, it also exhibits good mechanical and fluid dynamic properties that are suitable for... more
Among countless applications, chitosan has the potential to be an effective and cheap adsorbent for pollutant removal in (waste) water. In form of beads, it also exhibits good mechanical and fluid dynamic properties that are suitable for utilization in large-scale adsorption processes (e.g. as column packing). The present study investigates the beading process to prepare chitosan and cross-linked chitosan beads by phase inversion method. Beading parameters (i.e. chitosan amount, acid concentration, non-solvent agent concentration, and temperature) are optimized to obtain an appropriate adsorbent structure to uptake large organic molecules (reactive red 2, a dye, is utilized as model pollutant). Chitosan beads present remarkably enhanced adsorption capacity, mainly thanks to increased specific surface area and porosity. The addition of a cross-linker (diepoxyoctane) further improves pollutant removal. The adsorption process is well-fitted by the Freundlich model, suggesting a multilayer adsorption. The kinetic study also substantiates the complexity of the adsorption mechanism on bead surface, which, however, is satisfactorily predicted by a simple fractal kinetic model. Finally, it is proved that chitosan and cross-linked chitosan beads can be recycled (by washing with NaOH solution) at least 5 times before sensible performance loss.
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Wastewater treatment for water reuse has received considerable attention owing to water resource shortage. One of the most effective wastewater treatment methods involves the use of constructed wetlands (CWs). In this study, synthetic... more
Wastewater treatment for water reuse has received considerable attention owing to water resource shortage. One of the most effective wastewater treatment methods involves the use of constructed wetlands (CWs). In this study, synthetic wastewater was treated by using a biochar/zeolite CW. Phragmites australis (common reed) was translocated into two cylinders (lysimeters) that serve as vertical subsurface flow CWs. One CW (CW1) contained gravels as substrate layer, whereas the other CW (CW2) contained three substrate layers, namely, biochar, zeolite, and gravel layers. Response surface methodology was used for statistical analysis. In this study, CW2 performed better in removing pollutants from wastewater than CW1. At optimum pH (6.3) and retention time (57.4 h), 99.9% (1000 mg/L) COD, 99.9% (1000 mg/L) ammonia, 99.9% (50 mg/L) phenols, 99.9% (50 mg/L) Pb, and 99.9% (50 mg/L) Mn were removed by CW2. During this research, nitrous oxide emission was lower in CW2 than in CW1.
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Organic micropollutants (MPs) in low concentrations can affect aquatic ecosystems and human health. Adsorption technique is one of the promising methods to remove MPs. Chitosan and zeolites are environmentally friendly and low-cost... more
Organic micropollutants (MPs) in low concentrations can affect aquatic ecosystems and human health. Adsorption technique is one of the promising methods to remove MPs. Chitosan and zeolites are environmentally friendly and low-cost adsorbents. Thus, removal of organic MPs (such as bisphenol A (BPA), carbamazepine (CBZ), ketoprofen (KTF) and tonalide (TND) from aqueous solution via cross-linked chitosan/zeolite, as a fixed-bed column, was investigated in the current study. Hydraulic retention time was set at 0.8 h pH and concentration of organic MPs ranged from 4 to 8 and 0.50 mg/L to 2.0 mg/L, and they were considered as factors in optimizing the removal of pollutants via response surface methodology (RSM). Approximately 1.4560 mg/L (89.0%) of BPA, 1.4724 mg/L (90.0%) of CBZ, 1.4920 mg/L (91.2%) of KTF and 1.4118 mg/L (86.3%) of TND were removed at 5.1 pH and 1.636 mg/L initial concentration as the optimum removal efficiency on the basis of RSM. Artificial neural network (ANN) was used to optimise removal effectiveness for each MP. The high R2 values and reasonable mean squared errors indicated that ANN optimized MP removal in a logical aspect. Adsorption isotherm studies revealed that organic MP removal through chitosan/zeolite could be explained with Freundlich and Langmuir isotherms.
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Polycyclic aromatic hydrocarbons (PAHs) are principally derived from the incomplete combustion of fossil fuels. This study investigated the occurrence of PAHs in aquatic environments around the world, their effects on the environment and... more
Polycyclic aromatic hydrocarbons (PAHs) are principally derived from the incomplete combustion of fossil fuels. This study investigated the occurrence of PAHs in aquatic environments around the world, their effects on the environment and humans, and methods for their removal. Polycyclic aromatic hydrocarbons have a great negative impact on the humans and environment, and can even cause cancer in humans. Use of good methods and equipment are essential to monitoring PAHs, and GC/MS and HPLC are usually used for their analysis in aqueous solutions. In aquatic environments, the PAHs concentrations range widely from 0.03 ng/L (seawater; Southeastern Japan Sea, Japan) to 8,310,000 ng/L (Domestic Wastewater Treatment Plant, Siloam, South Africa). Moreover, bioaccumulation of ∑16PAHs in fish has been reported to range from 11.2 ng/L (Cynoscion guatucupa, South Africa) to 4207.5 ng/L (Saurida undosquamis, Egypt). Several biological, physical and chemical and biological techniques have been reported to treat water contaminated by PAHs, but adsorption and combined treatment methods have shown better removal performance, with some methods removing up to 99.99% of PAHs.
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The growing use of pharmaceuticals raises questions on their potential risk to human health and water quality. This research aimed to introduce a combined treatment technique with high performance in removing pharmaceutical... more
The growing use of pharmaceuticals raises questions on their potential risk to human health and water quality. This research aimed to introduce a combined treatment technique with high performance in removing pharmaceutical micropollutants (MPs) from aqueous solution. The research included two steps, ozone treatment (first step) and adsorption technique (second step). The elimination of acetaminophen (ACT) and amoxicillin (AMX) with ozone reactor, first step, was optimised by artificial neural network (ANN). The optimisation process included two independent variables, namely, initial concentration of MPs and ozone dosage. On the basis of ANN, the linear regression coefficient denoted by R2 between predicted and experimental MP removals was close to 1. Result displayed that the prediction by the trained ANN is acceptable. Approximately 0.17 mg/L (84.8%) of ACT and 0.16 mg/L (82.7%) of AMX were removed at the initial concentration of 0.2 mg/L and ozone dosage of 15 mg/L. Beside it, ozonation experiments showed that the rate of constant (m−1s−1) for ACT and AMX were 2.63×106 and 5.98 ×106, respectively. After treating by ozone reactor, water was subjected to pass through the cross-linked chitosan/bentonite as a fixed-bed column, for second step. ACT and AMX were not detected after step 2.
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One of the most important types of emerging micropollutants is the pharmaceutical micropollutant. Pharmaceutical micropollutants are usually identified in several environmental compartments, so the removal of pharmaceutical... more
One of the most important types of emerging micropollutants is the pharmaceutical micropollutant. Pharmaceutical micropollutants are usually identified in several environmental compartments, so the removal of pharmaceutical micropollutants is a global concern. This study aimed to remove diclofenac (DCF), ibuprofen (IBP), and naproxen (NPX) from the aqueous solution via cross-linked magnetic chitosan/activated biochar (CMCAB). Two independent factors-pH (4-8) and a concentration of emerging micropollutants (0.5-3 mg/L)-were monitored in this study. Adsorbent dosage (g/L) and adsorption time (h) were fixed at 1.6 and 1.5, respectively, based on the results of preliminary experiments. At a pH of 6.0 and an initial micropollutant (MP) concentration of 2.5 mg/L, 2.41 mg/L (96.4%) of DCF, 2.47 mg/L (98.8%) of IBP, and 2.38 mg/L (95.2%) of NPX were removed. Optimization was done by an artificial neural network (ANN), which proved to be reasonable at optimizing emerging micropollutant elimination by CMCAB as indicated by the high R 2 values and reasonable mean square errors (MSE). Adsorption isotherm studies indicated that both Langmuir and Freundlich isotherms were able to explain micropollutant adsorption by CMCAB. Finally, desorption tests proved that cross-linked magnetic chitosan/activated biochar might be employed for at least eight adsorption-desorption cycles.
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Eliminating organic and inorganic pollutants from water is a worldwide concern. In this study, we applied electrochemical oxidation (EO) and adsorption techniques to eliminate ammonia, phenols, and Mo(VI) from aqueous solutions. We... more
Eliminating organic and inorganic pollutants from water is a worldwide concern. In this study, we applied electrochemical oxidation (EO) and adsorption techniques to eliminate ammonia, phenols, and Mo(VI) from aqueous solutions. We analyzed the first stage (EO) with response surface methodology, where the reaction time (1–3 h), initial contaminant concentration (10–50 mg/L), and pH (3–6) were the three independent factors. Sodium sulfate (as an electrolyte) and Ti/RuO 2 –IrO 2 (as an electrode) were used in the EO system. Based on preliminary experiments, the current and voltage were set to 50 mA and 7 V, respectively. The optimum EO conditions included a reaction time, initial contaminant concentration, and pH of 2.4 h, 27.4 mg/L, and 4.9, respectively. The ammonia, phenols, and Mo elimination efficiencies were 79.4%, 48.0%, and 55.9%, respectively. After treating water under the optimum EO conditions, the solution was transferred to a granular composite adsorbent column containing bentonite, limestone, zeolite, cockleshell, activated carbon, and Portland cement (i.e., BAZLSC), which improved the elimination efficiencies of ammonia, phenols, and molybdenum(VI) to 99.9%. The energy consumption value (8.0 kWh kg −1 N) was detected at the optimum operating conditions.
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Wastewater filtration is considered the main solution to water shortages. Here, we treated synthetic wastewater by combining treatment techniques, namely, electrochemical oxidation and adsorbent added sequencing batch reactor (SBR). One... more
Wastewater filtration is considered the main solution to water shortages. Here, we treated synthetic wastewater by combining treatment techniques, namely, electrochemical oxidation and adsorbent added sequencing batch reactor (SBR). One beaker with a working value of 1500 mL was applied in this contemporary study. In the upper part of the beaker, an anode and a cathode (Ti/RuO 2-IrO 2) were arranged in parallel for the electrochemical oxidation process. Sodium sulfate (Na 2 SO 4) with a concentration of 2.5 g/L was added as the electrolyte. The voltage and current were set to 7.50 V and 0.40 A, respectively. Aeration was conducted at the bottom of the beaker. Then, 15% working value of the reactor was filled by activated sludge, and 85% working value of the reactor was added with synthetic wastewater. In addition, 1.50 g/L of powdered cockleshell was added in the reactor. Response surface methodology was used for statistical analysis. In synthetic wastewater, concentrations of COD, ammonia, phenols and chromium were 2500 mg/L, 2500 mg/L, 100 mg/L and 100 mg/L, respectively. pH and reaction time (h) were considered as independent factors. A total of 2430 mg/L biochemical oxygen demand, 2500 mg/L ammonia, 90.0 mg/L phenols, and 84.0 mg/L chromium were eliminated at the optimum reaction time (72.9 min) and pH (6.5). The energy consumption value was 6.5 (kWh kg −1) at the optimum operating conditions. This study indicated that this combined treatment system exhibited high performance.
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Heavy metals, such as vanadium, are some of the most toxic types of water contaminants. In this study, vanadium was removed using a new composite adsorbent called BAZLSC. The impacts of pH and initial concentration of vanadium(V) on the... more
Heavy metals, such as vanadium, are some of the most toxic types of water contaminants. In this study, vanadium was removed using a new composite adsorbent called BAZLSC. The impacts of pH and initial concentration of vanadium(V) on the elimination effectiveness of this metal by using BAZLSC were investigated in the first step of the study. Vanadium removal increased as pH increased to 3-3.5, and initial concentration increased to 60-70 mg/L. The removal efficiency then decreased. Central composite design and response surface methodology were employed to examine experimental data. Initial concentration of V (mg.L-1), pH, and dosage of adsorbent (g/L) were the independent factors. Based on RSM, the removal effectiveness of vanadium was 86.36% at the optimum of initial concentration (52.69 mg/L), pH (3.49), and adsorbent dosage (1.71 g/L). Also adsorption isotherm investigations displayed that the Freundlich isotherm could explain vanadium adsorption by BAZLSC better than the Langmuir isotherm. Beside them, desorption studies showed sorption was slightly diminished after six continuous cycles.
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(VI) removal from aqueous solutions using bentonite and powdered cockle shell; Optimization by response surface methodology, Abstract Removal of Mo(VI) from aqueous solutions by using bentonite and powdered cockle shell was conducted in... more
(VI) removal from aqueous solutions using bentonite and powdered cockle shell; Optimization by response surface methodology, Abstract Removal of Mo(VI) from aqueous solutions by using bentonite and powdered cockle shell was conducted in this research. First, the effects of pH and initial Mo(VI) concentration on the Mo removal efficiency via shell and bentonite were studied. Results showed that Mo removal effectiveness increased as pH increased until 3.5. Removal efficiency of Mo via bentonite and shell also increased as initial Mo(VI) concentration increased to 30 or 40 mg/L, respectively, after which the removal efficiency decreased. Response surface methodology and central composite design were applied to optimize removal effectiveness. Initial concentration of Mo(VI) (mg/L), pH, and shaking time (min) were selected as independent factors. These results showed that bentonite is more effective in removing Mo from water than the shell. At the optimum condition of 5.8 pH, initial Mo concentration of 39.2 mg/L, and shaking time of 38.6 min, bentonite could remove 81.3% of Mo.
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Air pollution is one of the main environmental problems in many cities around the world. Controlling this kind of pollution is more complex than other environmental challenges. Many plants can absorb and save some of the environmental... more
Air pollution is one of the main environmental problems in many cities around the world. Controlling this kind of pollution is more complex than other environmental challenges. Many plants can absorb and save some of the environmental pollutants through their leaves. Therefore, air pollution tolerance index (APTI) was tested in polluted and blank areas in six plant species, namely, Conocarpus, Myrtus, Prosopis, Eucalyptus, Ziziphus, and Lebbek, which are abundant in the Ahvaz region during 2014. Dust deposition on leaf surfaces was determined to observe the extent of particulate deposition. The highest and the lowest deposition rates were observed in Myrtus (maximum 80.3 g.m-2 in polluted site) and Lebbek (minimum 10.7 g.m-2 in blank site), respectively. The APTI was calculated to be 4.97 for Prosopis, 5.25 for Ziziphus, 6.24 for Lebbek, 6.59 for Conocarpus, 6.77 for Eucalyptus and 7.80 for Myrtus in blank site and 4.57 for Prosopis, 4.82 for Ziziphus, 5.79 for Lebbek, 5.84 for Eucalyptus, 6.30 for Conocarpus and 7.21 for Myrtus in the polluted area at the end of study. The APTI showed that Myrtus is resistant to plant pollution, whereas Prosopis is sensitive to plant pollution. In addition, the results of assessment of the above mentioned index showed that plants with higher APTI can be used as reducers of pollution and plants with lower APTI can be used to measure air pollution.
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Production of raw leachate from landfills regards as shortcoming for the sanitary landfills. Unprocessed landfill leachate requires treatment prior disposal to the natural environment. In this work, leachate channeling, biological, and... more
Production of raw leachate from landfills regards as shortcoming for the sanitary landfills. Unprocessed landfill leachate requires treatment prior disposal to the natural environment. In this work, leachate channeling, biological, and physical-chemical treatment processes for treatment of formed landfill leachate were presented in details. Definite treatment processes were resulted in high removal of pollutants such as ammonia (NH 3 -N), chemical oxygen demand (COD), biochemical oxygen demand (BOD 5), phenols, color etc. Practically, age of produced leachate have influence on the treatment systems. Efficient treatment methods were explained for fresh, medium, and stabilized landfill leachates.
ABSTRACT
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Abstract. The reuse of wastewater for purposes such as agricultural irrigation can reduce the amount of water that needs to be extracted from environmental water sources. The aims of the study were the effects of municipal wastewater on... more
Abstract. The reuse of wastewater for purposes such as agricultural irrigation can reduce the amount of water that needs to be extracted from environmental water sources. The aims of the study were the effects of municipal wastewater on soil properties and Lepidium sativum. Soil samples of 0 to 20 cm depth were taken from agricultural field in Isfahan (center of Iran). Lepidium sativum was transplanted in pots containing 7 kg of these soils.