River bed soil collected from Suruli Theertham, Theni District, Tamilnadu, India was characterized using Fourier Transform Infrared Spectroscopy (FT IR), X-ray powder diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy... more
River bed soil collected from Suruli Theertham, Theni District, Tamilnadu, India was characterized using Fourier Transform Infrared Spectroscopy (FT IR), X-ray powder diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDAX) techniques. FT-IR analysis revealed the presence of various functional groups of Si-O, Al-OH, Al-O, Si-O-Al bands which influence the adsorption process. Identification and estimation of mineralogical composition were carried out by XRD. XRD patterns indicate the presence of silicon dioxide and aluminium oxide in major quantities. SEM analysis showed the platy flakes and spongy structure of silica and alumina. Elemental analysis (EDAX) confirmed the presence of Si (20.66 %) in large quantities than the other oxides such as Al (9.76 %), Fe (6.52 %), Ca (3.05 %), Mg (0.59 %), Mn (0.14 %), Na (3.33 %), K (3.66 %) and phosphorous (0.02 %)
Toxic effect of textile dyes their increasing quantities in air, soil and water environments, because of growing of industrial activities, they must be taken into consideration since they give harm to the environment. We come across... more
Toxic effect of textile dyes their increasing quantities in air, soil and water environments, because of growing of industrial activities, they must be taken into consideration since they give harm to the environment. We come across textile dyes in natural wetlands as result of uncontrolled industrial wastes. Textile dyes that can accumulate easily in their environments may show toxic effects. Pumice, accruing as a result of volcanic events and durable against chemical factors, is a rock that has porous structure. Pumices have a porous structure because of sudden cooling of the rock and sudden leaving of gases a result of volcanic events. Thanks to these pores, pumices' heat and sound insulation are quite high. The most distinctive feature of pumice from other rocks is that it has different colors and there is not crystal water in its porous structure. Adsorption studies are applied with Van Pumice at pH = 6, the adsorption mechanism and changing dye concentration. As result of these researches, it has been found out that there are different adsorption movements at pH 6 between Neutral Red and Van Pumice. The result of this study shows that the Pumice found in Lake Van gives a better fit for the Langmuir Isotherm (model) and the amount of adsorption increases with the temperature. We thereby conclude that the Pumice located in Lake Van is a recommended adsorbent for filtering the used textile dye in aqueous medium.
According to the Greek philosopher Empedocles' interpretations, the attraction and repulsion contribute to the self-organization of a system of elements. We illustrated this by the examples of DNA replication and by olefin adsorption on... more
According to the Greek philosopher Empedocles' interpretations, the attraction and repulsion contribute to the self-organization of a system of elements. We illustrated this by the examples of DNA replication and by olefin adsorption on supports. Olefins polymerizations by Ziegler-Natta, Phillips, and metallocene complexes are interpreted by a charge percolation mechanism. Research paper
Biphasic apatite-carbon biochar-type materials were prepared from pyrolysed cod fish bones and were assessed for the adsorption of persistent organic pollutants (pharmaceuticals diclofenac and fluoxetine), and heavy metals (Pb(II)). The... more
Biphasic apatite-carbon biochar-type materials were prepared from pyrolysed cod fish bones and were assessed for the adsorption of persistent organic pollutants (pharmaceuticals diclofenac and fluoxetine), and heavy metals (Pb(II)). The materials, prepared with a simple pyrolysis process at different temperatures (200–1000 °C), were characterised with XRD, FTIR, Raman and SEM. Results showed that the pyrolysis temperature had a significant effect on the features / composition of the materials: up to 800 °C, carbonate apatite Ca10(PO4)6(CO3) was the main component, while for higher temperatures oxyapatite Ca10(PO4)6O was the dominant phase. Graphitic carbon was also detected. The mixed apatite-carbon products (bone char) exhibited high adsorption efficiency. Graphite carbon was the main adsorber for the pharmaceuticals, the best performing material being that pyrolysed at 1000 °C. X m values of 43.29 and 55.87 mg/g were observed (Langmuir fitting), while K F values of 5.40 and 12.53 (mg/g)(L/mg) n F were obtained with the Freundhlich model (diclofenac and fluoxetine respectively). This is the first time that a biochar-like material has been used for fluoxetine adsorption. For Pb (II), the powder pyrolysed at 600 °C was the most effective, with the apatite playing a key role (X m = 714.24 mg/g). This work shows that a by-product of the fish industry could be converted into efficient materials for environmental remediation; according to the pyrolysis conditions, powders effective in the removal of either organics or heavy metals can be obtained. Moreover, with pyrolysis at intermediate temperatures, materials capable of adsorbing both kinds of pollutants can be produced, even if less efficient.
The search for optimal fluid/adsorbent working pairs in adsorption heat transformers is featured by trial and error method. In the last decades this approach has produced relevant progresses especially resulted in new advanced adsorption... more
The search for optimal fluid/adsorbent working pairs in adsorption heat transformers is featured by trial and error method. In the last decades this approach has produced relevant progresses especially resulted in new advanced adsorption materials. On the refrigerant fluid side water, ammonia, methanol and ethanol still seem to be the only viable options. This work aims to explain the reason of that and the requirement that a refrigerant fluid must fulfil in order to be considered as promising for adsorptive cooling and heating. A thermodynamic framework is developed that merges the corresponding states principle with the characteristic curve of adsorption. Finally the framework is applied to assess the theoretical coefficient of performance of 258 fluids on 16 adsorption materials belonging to activated carbons, silica gels and zeolites, by avoiding in this way blind search strategy of the optimal working pair. Furthermore, the approach is used also to identify more generally the refrigerant thermodynamic properties for maximum performance. Fluid critical temperature is often the chief property enabling higher performance, although not always all the adsorption materials share the same sensitivity to the same thermodynamic properties.
The present study addresses the application of raw and modified carbon nanotubes (CNTs) and activated carbon (AC) for the removal of hexavalent chromium (Cr(VI)) from aqueous solution. Surfaces of both the adsorbents were modified by acid... more
The present study addresses the application of raw and modified carbon nanotubes (CNTs) and activated carbon (AC) for the removal of hexavalent chromium (Cr(VI)) from aqueous solution. Surfaces of both the adsorbents were modified by acid treatment. Nitric acid was used to remove impurities and to introduce carboxylic functional groups on the surfaces of CNTs and AC. Raw and modified adsorbents (CNTs and AC) were characterized by scanning electron microscopy, Brunauer–Emmett–Teller surface area analysis, and thermogravimetric analysis. The influence of adsorbent dosage, contact time, agitation speed, and solution pH were evaluated on the Cr(VI) removal efficiency using batch adsorption experiments. The optimum pH for maximum adsorption of Cr(VI) was found to be 3 and 4 for AC and CNTs, respectively. Modified and raw AC were able to remove 99 and 92% of Cr(VI) ions, respectively, at 75 mg adsorbent dosage, agitation speed of 200 rpm, initial Cr(VI) concentration of 1 mg/L, contact time of 4 h, and solution pH 3, while the removal of Cr(VI) ions recorded maximum values of 87 and 80% for modified and raw CNTs under same treatment conditions. However, acid modification of CNTs was found to have no major effect on the percentage removal of Cr(VI) ions at low adsorbent dosage. Adsorption capacities of both the adsorbents were determined using batch adsorption experiments and experimental data were described by Langmuir and Freundlich adsorption isotherm models. However, Langmuir isotherm model was able to best describe the adsorption of Cr(VI) ions on raw and modified forms of CNTs and AC. Maximum adsorption capacity (qe) was found to be 2.024 and 1.805 mg/g for raw and modified AC, while 1.021 and 0.964 mg/g for raw and modified CNTs.
The adsorption characteristics of methane on granular activated carbon were measured over the temperature range of (293 to 323) K and at pressures up to 900 psi using a volumetric measurement system. The surface of activated carbon has... more
The adsorption characteristics of methane on granular activated carbon were measured over the temperature range of (293 to 323) K and at pressures up to 900 psi using a volumetric measurement system. The surface of activated carbon has been modified with copper oxides and sliver in order to improve the adsorption capacity of methane. The results indicate that the adsorption capacity can be marginally improved by doping small amount of metal oxides The adsorption data were fitted to different isotherm model s and the result shows that DA are able to predict data correctly at all temperature . The isosteric heat of adsorption, which is concentration and temperature dependent, is extracted from the data.
The search for optimal fluid/adsorbent working pairs in adsorption heat transformers is featured by trial and error method. In the last decades this approach has produced relevant progresses especially resulted in new advanced adsorption... more
The search for optimal fluid/adsorbent working pairs in adsorption heat transformers is featured by trial and error method. In the last decades this approach has produced relevant progresses especially resulted in new advanced adsorption materials. On the refrigerant fluid side water, ammonia, methanol and ethanol still seem to be the only viable options. This work aims to explain the reason of that and the requirement that a refrigerant fluid must fulfil in order to be considered as promising for adsorptive cooling and heating. A thermodynamic framework is developed that merges the corresponding states principle with the characteristic curve of adsorption. Finally the framework is applied to assess the theoretical coefficient of performance of 258 fluids on 16 adsorption materials belonging to activated carbons, silica gels and zeolites, by avoiding in this way blind search strategy of the optimal working pair. Furthermore, the approach is used also to identify more generally the r...
Pu-Erh tea (PET) is a fully fermented tea cultivated in the Yunnan Province of China. It iswidely appreciated and consumed as the healthful beverage. In vivo, in vitro and clinical studies have suggested the health benefits of PET for a... more
Pu-Erh tea (PET) is a fully fermented tea cultivated in the Yunnan Province of China. It iswidely appreciated and consumed as the healthful beverage. In vivo, in vitro and clinical studies have suggested the health benefits of PET for a variety of hypolipidemic, antiobesity, antimutagenic, antioxidative, antitumor, free radical scavenging and toxicity suppressing activities. Many of these beneficial impacts are related to its bioactive compounds, particularly theabrownin and gallic acid. However, there are some scientific evidences underlying the risk of pathological abnormalities associated with the high doses of PET extracts. Confirming the assertion, this paper presents a state of art reviewof PET, its tasting, sensory evaluation and aroma characterization. The key advances of itswide implications in the adsorption engineering, toxicological, pharmacological andmedical science development are laconically elucidated. Furthermore, the challenges and future prospects for the integration of PET practice are outlined.
