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New simple sensitive spectrophotometric methods are developed for determination of cefepime (CFM) in pure and Pharmaceutical Formulations. The first method conversion primary amine to azo-dye by react cefepime with sodium nitrite and hydrochloric acid followed by coupling with 3-aminophenol in alkaline medium to obtain a stable orange colored dye at λ max 495 nm. The concentration ranges 2–50 μg / mL, Beer's law is obeyed, correlation coefficient was 0.9997, molar absorptivity was 0.704 × 104L.mol−1.cm−1 and the detection limit was 0.259 μg/mL. Cloud point extraction (CPE) second method to estimation a trace amount in aqueous solution product from diazotization and measuring with a UV–visible spectrophotometer at λ max 495 nm. The concentration range obeyed the Beer's law was 0.25–10 μg / mL, correlation coefficient was 0.9996, molar absorptivity was 1.362 × 105L.mol−1.cm−1, detection limit was 0.013 μg/mL, Pre-concentration factor was 25 and Distribution coefficient(D) was 333.35.

This work demonstrates the potential of calcium- and nickel-crosslinked Gellan Gum (GG) microspheres to capture the Six-Transmembrane Epithelial Antigen of the Prostate 1 (STEAP1) directly from complex Komagataella pastoris mini-bioreactor lysates in a batch method. Calcium-crosslinked microspheres were applied in an ionic exchange strategy, by manipulation of pH and ionic strength, whereas nickel-crosslinked microspheres were applied in an affinity strategy, mirroring a standard immobilized metal affinity chromatography. Both formulations presented small diameters, with appreciable crosslinker content, but calcium-crosslinked microspheres were far smoother. The most promising results were obtained for the ionic strategy, wherein calcium-crosslinked GG microspheres were able to completely bind 0.1% (v/v) DM solubilized STEAP1 in lysate samples (~7 mg/mL). The target protein was eluted in a complexed state at pH 11 with 500 mM NaCl in 10 mM Tris buffer, in a single step with minimal losses. Coupling the batch clarified sample with a co-immunoprecipitation polishing step yields a sample of monomeric STEAP1 with a high degree of purity. For the first time, we demonstrate the potential of a gellan batch method to function as a clarification and primary capture method towards STEAP1, a membrane protein, simplifying and reducing the costs of standard purification workflows. [ABSTRACT FROM AUTHOR]

• Design and synthesis of pro-active nano metal oxides. • Advanced and cost-effective process for water treatment. • Comparative study probed the efficacies of target compound in heavy metal removal. • Upscaling the lab result to field samples to batch (96 %) and column method (98 %). Unprocessed solutions containing hazardous heavy metals, even in trace amounts, exert a detrimental impact on human health and pose a threat to biodiversity, hydrosphere ecosystems, and communities. Liquid waste containing heavy metals has been found to pose a notable threat to the environment. In this study, nano NiO, MnO, and NiMnO 3 were synthesized and characterized systematically. The nano metal oxides were used as an adsorbent for the elimination of heavy metals from industrial wastewater. In view of this, the efficacy of synthesized metal oxides as potential sorbents is investigated to chelate Pb (II) ions which are present as one of the major contaminants of industrial effluents. Three adsorption systems viz., Pb(II) – NiO, Pb(II) - MnO, and Pb(II) – NiMnO 3 mixture were experimentally verified by Batch equilibration and fixed bed column methods. Pre and post-run sorbent materials are characterized using SEM and EDAX analyses to examine the appropriate changes. A trial fixed bed column was run for the effluent sample, wherein 98% Pb (II) removal was registered against 96 % as observed in Batch mode. This emphasizes the potential of the synthesized metal oxides as efficient sorbents for addressing heavy metal contamination in industrial wastewater. [Display omitted] [ABSTRACT FROM AUTHOR]

The first method on the oxidative coupling Amoxixilin reaction with 2,4- dinitrophenyl hydrazine and Sodium Iodate diluted to produce a soluble red-Orange dye product was devised to estimate the Amoxicillin in bulk and pharmaceutical preparation. The concentration range is between 1 and 50 g/mL. Beer's law is met by the product in terms. With a molar absorptivity of 6.2×10³ L.mol-1.cm-1 and a correlation coefficient of 0.9995, Sandell's sensitivity is 0.059g.cm-2 at 475 nm. A second technique for determining a trace amount in an aqueous solution product is called cloud point extraction (CPE), and it is based on measurements made with a UV-visible spectrophotometer at a wavelength of 480 nm. The correlation coefficient was 0.9996 and the Beer's law concentration range was 0.25–6 g/mL The molar absorptivity was 103623.79 L.mol-1.cm-1. Pre-concentration 25, detection of limit 0.023 µg/mL. The distribution coefficient (D) was 158.6, and enrichment factor was 28.35. The last method is flow injection analysis, which is straightforward to estimate. The Beer's law concentration range was 2-150 µg / mL, Sandell's sensitivity is 0.13 µg.cm-2 at 475 nm, with a molar absorptivity of 2.8×10³ L.mol-1.cm-1 and correlation coefficient was 0.9996, it is successfully used for drug estimation. Qualities in a straightforward situation or pharmacological formulations. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Petroleum Research & Studies is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This research investigated the adsorption of Cr(VI) using HNO3 0,01 M-activated rice straw in a batch system. Some parameters such as pH, initial Cr(VI) concentration, and contact times were examined. The optimum conditions were achieved at the pH 3, initial Cr(VI) concentration 800 mg/L in 15 min with adsorption capacity 60.204 mg/g. It was found that the adsorption of Cr(VI) onto activated rice straw was followed the Freundlich isotherm model (R² = 0.9957) and pseudo-second-order model (R2 = 0.9995) indicating that adsorption chemically occurred and multilayer. Whereas the thermodynamic study revealed that Cr(VI) adsorption onto activated rice straw was exothermic (ΔH° = -8.658 kJ/mol) non-spontaneous reaction (ΔG° = positive) with liquid/solid interface disorder (ΔS° = -65,297 J/mol). The physicochemical characterization of the bioadsorbent showed a wavenumber shifting of some functional groups. The percentage of Cr(VI) in bioadsorbent increased and the surface morphology of the bioadsorbent was smoother after adsorption occurred. Thus, this locally abundant rice straw could be used as a bioadsorbent for Cr(VI) removal. [ABSTRACT FROM AUTHOR]

The change of the oxygen equilibrium partial pressure in the gas phase makes it possible to identify the synthesis conditions and operating modes of oxide materials. The effect of oxygen pressure on heterogeneous equilibria in the R–Mn–O (R = Y, Ho–Lu) systems was studied by a batch method during thermal dissociation of RMn2O5 and RMnO3 manganites. The reduction sequence of oxides was elucidated. The temperature-dependent equilibrium oxygen pressure was determined in the range 973–1220 K for monovariant equilibria of RMn2O5 and RMnO3 reduction, and the thermodynamic functions of formation from elements were calculated for the manganites. The thermal stability of RMn2O5 and RMnO3 was determined as dependent on the ionic radius and the number of unpaired 4f electrons of the lanthanide. [ABSTRACT FROM AUTHOR]

Abstract The groundwater samples were found to be contaminated with high concentrations of uranium (U) in Punjab state as well as in few other locations of India. U being chemically toxic can deteriorate health when ingested. Hence, there is a need to remove U from contaminated water using an efficient, cheap and user friendly method. A study was initiated to investigate the efficiency of low-cost adsorbents in removing U from water. Seven adsorbents were screened for U removal efficiency, among which fly ash (FA) and tea waste (TW) were found to have better removal efficiency. Solid–liquid contact time and solution pH were optimized to establish conditions for better U removal efficiency. The U adsorption on FA and TW followed pseudo-second-order kinetics with rate constant values 4.63 g/mg/min and 15.63 g/mg/min, respectively. FA and TW had the highest U removal capability at pH 6 and pH 4, respectively. The U sorption data were fitted with Freundlich and Dubinin–Radushkevich isotherm models. The U adsorption on FA and TW is found to be a physical process with mean free energy (E) values less than 8 kJ/mol. Theoretically calculated maximum adsorption capacity values indicate that FA is a better adsorbent as compared to TW, which has been further confirmed experimentally. The U adsorption on both the adsorbents has interference from Ca2+ and no interference from Fe3+ at tested U concentrations. It is also found that FA and TW are effective in decontaminating U from spiked real groundwater samples to below the WHO (Guidelines for drinking water quality, 4th ed, vol 1, World Health Organization, Geneva, 2011) limit.

In present investigate the possible removal of Ni2+ ions from aqueous solution by using lowcost Hygrophila auriculata activated nano carbon (HA-ANC) as an adsorbent. The activated nano carbon had been prepared from Hygrophila auriculata stem waste as well; the raw material was carbonized with con. H2SO4 and activated by thermal action. Batch experiments were performed in order to calculate the percentage removal of Ni2+ ions for 90.737% at 60oC. The properties of treated carbon and untreated carbon are compared using instrumental techniques such as FT-IR, XRD, SEM and EDX, which confirms Ni2+ ions adsorption onto HA-ANC. FT-IR showed that the surface of HA-ANC had more oxygen containing functional groups which enhanced the adsorption of Ni2+. XRD showed the nature of adsorbent, SEM images implies morphological deviance of before and after adsorption of Ni2+ onto HA-ANC and EDX showed that the C content of HA-ANC were higher than that of Ni2+/HA-ANC. [ABSTRACT FROM AUTHOR]

A new poly(methacrylic acid-co-itaconic acid) [poly(MAA-co-IA)] hydrogel encapsulated copper hexacyanoferrate (CuHCF) nanoparticles was synthesized. The prepared samples were characterized by Fourier-transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray, transmission electron microscopy, X-ray diffraction, and thermogravimetric analysis-differential scanning calorimetry. The prepared composite CuHCF/poly(MAA-co-IA) was examined for adsorption of Cs+ by batch technique. The effect of various factors like solution pH, Cs+ initial concentration, agitation time, the temperature of the solution, and competition ions was investigated. CuHCF/poly(MAA-co-IA) composite exhibited high adsorption capacity (1.48 mmol g-1) of Cs+ occur at a pH equal to 9, initial concentration of 8 mmol L-1 Cs+ at room temperature (25°C). The adsorption of Cs+ was kinetically rapid, and the equilibrium was reached within 40 min. Between Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich isotherms models, the data were well fitted with the Langmuir model, suggesting that the uptake of Cs+ was monolayer and homogeneous. The adsorption kinetics parameters were fitted well to the pseudo-second-order model, and the Elovich equation indicated that chemisorption is the predominant adsorption mechanism. The intraparticle diffusion model shows that more than one controlling step may influence Cs+ loading. Thermodynamic parameters were calculated in the temperature range of 25°C-55°C and revealed that Cs+ sorption was endothermic, spontaneous, and more favourable at the higher temperature. The selectivity of the composite for Cs+ in the existence of Na+ and K+, Li+, Ca++ Mg++ ions was exceptional. Up to 98% desorption of Cs+ was completed with 2M KCl. [ABSTRACT FROM AUTHOR]

In the present study, the influence of coal fly ash's particle size on uranium (U) decontamination from water samples is investigated. Accordingly, fly ash is segregated into five different size fractions (i.e., 63–90 μm, 125 μm) using an electromagnetic sieve shaker. Adsorption experiments are carried out in triplicate samples (for equilibration time at pH 6) using a laboratory batch method on all the size fractions with known U concentration. The highest U adsorption is observed for the lowest size fraction (i.e.,

In present scenario, there is need to develop adsorbent based and cost-effective water purifier for removal of radiological and toxic metal ion contaminants viz. cesium, strontium and cobalt from contaminated water. In this regard, modified montmorillonite was prepared using reaction with hydrogen peroxide and potassium di-hydrogen phosphate and obtained product was characterized by different spectroscopic techniques viz. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The obtained modified montmorillonite was evaluated for removal of Cd(II), Co(II), Cs(I), Ni(II) and Sr(II) from contaminated water. Various factors which affect adsorption of metal ions on modified montmorillonite viz. contact time, initial concentration of metal ions and pH were studied. The batch method has been employed to determine adsorption capacity for metal ions in solution from 1000–10 000 μg/L, contact time 5–30 min, pH 4–10 and material quantities 50–200 mg at room temperature. The obtained adsorption data were fitted to Freundlich and Langmuir isotherm models; both models were found applicable for the metal ions adsorption on modified montmorillonite. The adsorption data were shown to follow pseudo second order reaction kinetics as per kinetic studies. The maximum adsorption capacity obtained 1.65–2.82 mg/g for Cd(II), Co(II), Cs(I), Ni(II) and Sr(II) metal ions. The results show that modified montmorillonite have great potential to remove Cd(II), Co(II), Cs(I), Ni(II) and Sr(II) from aqueous solutions through chemisorption and physio-sorption. Modified montmorillonite can be used for removal of radiological and toxic metal ion contaminants from contaminated water. [ABSTRACT FROM AUTHOR]

The importance on the removal of Cu2+ from the aqueous solution using activated Sida cordifolia carbon is narrated elaborately in the present study. The parameters studied included contact time, adsorbent dose, initial pH and other ionic effects. Freundlich and Langmuir isotherm models were applied to the equilibrium experimental data. The maximum adsorption capacity (qm) obtained from the Langmuir isotherm linear plots were 62.548, at an initial pH of 6.8 at 30°C. Thermodynamic data indicated that the process was endothermic, spontaneous and feasible. The adsorption followed pseudo second order reaction equation and the rate is mainly controlled by intra-particle diffusion. As a result, ASCC could be an important low-cost adsorbent for removal of Cu2+ from aqueous solution. [ABSTRACT FROM AUTHOR]

[Display omitted] The steel production generates approximately 10 % of electric arc furnace slag on the production of each ton of steel. In the view of environmental concerns and government regulations regarding slag disposal, alternate ways of its utilization are required. This work is focused on the leaching behaviour study of electric arc furnace (EAF) slag to assess its suitability as construction material. EAF slag contains toxic metals; consequently, their leachable quantity may affect the eco-system. Chromium (Cr), lead (Pb), mercury (Hg), molybdenum (Mo) and cadmium (Cd) have found special concern due to their high toxicity for human kind as well as for the environment. The leaching study of EAF slag was carried out through the application of sequential batch water leaching tests (SWLT), batch test and toxicity characteristics of leaching procedure (TCLP) method. Fresh EAF slag was characterized by XRF, XRD, SEM and ICPMS analysis for the determination of essential compositions and contamination. SWLT was performed at different pH of 4.0, 5.3, 6.1, 7.2 and 8.5. It was found that toxic metals was not leached beyond permissible limits at any pH. Moreover, TCLP method was applied for the leaching analysis of EAF slag at pH of 4.93 and 2.88. The concentrations of toxic metals in leachates were found negligible through ICP-OES analysis. The batch test method was also applied upto 60 days of EAF slag. This test was carried out at various pH ≈ 4, 5 and 6. The obtained leachates were tested at 10 days, 15 days, 30 days, 45 days and 60 days of leaching. The ICP-OES analysis of leachates showed negligible concentrations of leached metals/elements. Through the application of different leaching test methods, it was found that the leaching of hazardous heavy metals from EAF slag is negligible or within permissible limits as per IS 383−2016 and EPA. Therefore, EAF slag can be utilized as construction material in eco- friendly manner. [ABSTRACT FROM AUTHOR]

The present work shows the application of nickel- and magnesium-crosslinked gellan microspheres in ionic and affinity capture strategies to directly extract hSCOMT from the complex Komagataella pastoris lysate through a simple batch method. Both formulations present similar morphology, but nickel–crosslinked microspheres present higher crosslinker content and smaller diameters. Four different capture strategies were established, by manipulating the ionic strength, pH, temperature and competing agents' presence. The most promising results for hSCOMT capture and clarification were obtained employing an ionic strategy with nickel-crosslinked microspheres and an affinity strategy with magnesium-crosslinked microspheres at 4 °C. The bioactivity results (200%) and purification degree (70%) of hSCOMT captured by the ionic strategy were more satisfactory probably due to the soft ionic conditions used (100 mM NaCl). For the first time, the gellan polysaccharide versatility was demonstrated in the microsphere application for the direct capture of hSCOMT from a complex lysate, simplifying isolation biotechnological procedures. Unlabelled Image • Formulation and characterization of gellan microspheres reinforced with nickel and magnesium crosslinkers • Human SCOMT capture at 4 °C employing an ionic strategy with nickel-crosslinked microspheres • Human SCOMT capture at 4 °C employing an affinity strategy with magnesium-crosslinked microspheres • The ionic strategy with nickel-crosslinked microspheres, allows a bioactivity recovery under 200%. [ABSTRACT FROM AUTHOR]

In this study, a new category of sulfone-modified chitosan derivatives as surface-selective adsorbents for the extraction of toxic Hg(II) metal has been synthesized in good yield. Sulfone-modified chitosan/5–20 based on variable loading of the corresponding phenacyl bromide (5, 10, 15, and 20% with respect to the original weight of the pure chitosan) was synthesized. The β-ketosulfone derivative, namely 1–(4-bromophenyl)-2-(phenylsulfonyl)ethanone, was first prepared by treatment of the corresponding phenacyl bromide with a sufficient amount of sodium benzene sulfinate; its chemical structure was confirmed by spectral analyses, including Fourier transform infrared spectroscopy, 1H-NMR, 13C-NMR, and mass spectrometry. Then, sulfone-modified chitosan/5–20 derivatives were synthesized by the interaction of chitosan with a freshly prepared p-bromo-β-ketosulfone derivative in a mildly acidic aqueous solution using the solution-blending technique. Sulfone-modified chitosan/5–20 derivatives were identified and characterized using common characterization techniques, including Fourier transform infrared spectroscopy, field-emission scanning electron microscope, powder X-ray diffraction, and thermal behaviour. A strong interaction was displayed between chitosan and its corresponding β-ketosulfones in powder X-ray diffraction, which was confirmed by significant 2θ shifts. Sulfone-modified chitosan/5–20 derivatives were detected as catalysts, which efficiently increased the thermal decomposition of pure chitosan. More particularly, the efficiency of sulfone-modified chitosan/5–20 derivatives for Hg(II), Pb(II), Ni(II), Al(III), Sr(II), Cr(III), Fe(III), Zn(II), and Mn(II) detection and adsorption was also investigated using inductively coupled plasma optical emission spectrometry. The sulfone-modified chitosan/5 derivative exhibited the highest adsorption efficiency. The most effective quantitative adsorption onto the sulfone-modified chitosan/5 surface was detected at pH = 2. In addition to that, the adsorption isotherm showed that the adsorption capacity of sulfone-modified chitosan/5 for Hg(II) was 122.47 mg g−1 and that its adsorption isotherm was in agreement with the Langmuir adsorption isotherm. [ABSTRACT FROM AUTHOR]

The phosphorus (P) chemistry of biochar (BC)-amended soils is poorly understood. This statement is based on the lack of published research attempting a comprehensive characterization of biochar’s influence on P sorption. Therefore, this study addressed the kinetic limitations of these processes. This was accomplished using a fast pyrolysis biochar made from a mix of waste materials applied to a highly weathered Latossolo Vermelho distrofico (Oxisol) from São Paulo, Brazil. Standard method (batch method) was used. The sorption kinetic studies indicated that P sorption in both cases, soil (S) and soil-biochar (SBC), had a relatively fast initial reaction between 0 to 5 min. This may have happened because adding biochar to the soil decreased P sorption capacity compared to the mineral soil alone. Presumably, this is a result of: (i) Inorganic phosphorus desorbed from biochar was resorbed onto the mineral soil; (ii) charcoal particles physically covered P sorption locations on soil; or (iii) the pH increased when BC was added SBC and the soil surface became more negatively charged, thus increasing anion repulsion and decreasing P sorption.

The aim of the present study is to investigate the removal of nickel ions from aqueous solutions using natural zeolite. Batch experimental studies were conducted to evaluate by changing relevant parameters such as initial pH of solution, dosage of adsorbent, contact time, initial nickel ion concentration and temperature. The experimental isotherm data are analyzed using Langmuir and Freundlich equations. The Langmuir model fits the equilibrium data better than the Freundlich model. According to the Langmuir equation, the maximum uptake for nickel ions is 18.09 (mg/g). Pseudo-first-order and pseudo-second-order models are used to represent the kinetics of the process. The results indicate that the pseudo-second-order model is the one that best describes the kinetics of the adsorption of metal ions. The calculated thermodynamic parameters (ΔG°, ΔH°, and ΔS°) show that the adsorption process is feasible, spontaneous and endothermic at 20-50°C. Based on the experimental results, it can be concluded that natural zeolite has the potential of application as an efficient adsorbent for the removal of heavy metals from aqueous solutions.

The study deals with sorption and diffusion behaviour of strontium in Czech bentonite B75. The study is a part of a research on reactive transport of radioactive contaminants in barrier materials of a deep geological repository of radioactive waste in the Czech Republic. Series of sorption and diffusion experiments with Sr and non-activated Ca bentonite B75 produced in the Czech Republic were performed in two background solutions (CaCl2 and NaCl). On the basis of sorption batch experiments the kinetics of strontium sorption on bentonite was assessed and the sorption isotherms for various experimental conditions were obtained. As a result of performed diffusion experiments the parameters of diffusion (i.e. effective diffusion coefficient De and apparent diffusion coefficient Da) were determined. The observed discrepancies between sorption characteristics obtained from the sorption and diffusion experiments are discussed.

The objective of this work is to find a new, efficient and alternate low-cost adsorbent for preconcentration and spectrophotometric determination of uranyl ions U(VI) from aqueous solution. For this reason the new impregnated resin (ZnO/7HP) has been prepared by sol-gel technique. Characterization of ZnO/7HP was conducted using scanning electron microscopy/energy-dispersive X-ray spectrometer and X-ray diffraction, and Fourier transforms infrared spectroscopy. Several important parameters influencing the U(VI) adsorption such as pH, adsorbent amount, initial U(VI) concentration, contact time and temperature were investigated systematically by batch experiments. The obtained results showed that the equilibrium adsorption data were well fitted to the Langmuir model with a maximum adsorption amount of 24.96 mg/g. While the adsorption kinetics data were described well by the pseudo-second order model. This result indicates that the adsorption process is chemisorption. Thermodynamic results indicate that the U(VI) adsorption process is endothermic nature and favors at high temperature. Hydrochloric acid was used for preconcentration of U(VI) and detected spectrophotometry after the reaction with Arsenazo III. According to the definition of International Union of Pure and Applied Chemistry, the detection limit of this method was 0.12 μg/L. The relative standard deviation under optimum conditions is less than 3.0 % (n=5). The new impregnated resin ZnO/7HP is a promising adsorbent for preconcentration and spectrophotometric determination of U(VI) in aqueous solutions. [ABSTRACT FROM AUTHOR]

Copyright of Environnement, Risques & Santé is the property of John Libbey Eurotext Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copper hexacyanoferrate–carbomer composite (CuHCF-carbomer) was synthesized and used as an ion exchanger for the removal of hazardous cesium ion from aqueous solution. The composite composition, properties and morphology were characterized by several techniques namely, FTIR, SEM, EDX, XRD and TGA-DSC. The influence of pH of aqueous solution, initial concentration, shaking time and solution temperature on the adsorption of cesium onto CuHCF-carbomer composite were studied by batch technique. Maximum adsorption capacity value of 1.74 mmol g −1 of Cs + on CuHCF-carbomer was obtained at pH 9, 9 mmolL −1 Cs + , and 25 °C. Adsorption isotherms, kinetic and thermodynamic parameters of the adsorption process were obtained and used to describe the adsorption of Cs + . In addition, column method was used in the same purpose of Cs + ion removal. The effect of bed depth and flow rate on the adsorption characteristics of composite was examined at the optimum conditions of pH = 9 and initial Cs + concentration = 5 mmoL −1 . Thomas and Yoon–Nelson kinetic models were applied to evaluate column adsorption performance. Moreover, the prepared composite could be regenerated effectively by 2 M KCl and was used successfully for five times. [ABSTRACT FROM AUTHOR]

The objectives of this study were to investigate the adsorption of Cu-II and Zn-II on montmorillonite and bauxite and to discuss the usability of these adsorbents in environmental applications. The maximum adsorption was found for Cu (II) on bauxite with a Kf value of 4.179 L g−1; the maximum adsorbed capacity (Qo) calculated from the Langmuir model reached 9.115 mg g−1. Both raw materials have the potential to be effectively used to produce low-cost sorbents for copper and zinc removal from wastewater. They could be used as alternative adsorptive barriers and as amendments to soils at old mining areas, to prevent metal leaching into groundwater, or to isolate urban waste leachate. [ABSTRACT FROM AUTHOR]

An iminodiacetate (IDA) group containing nonwoven polyethylene (PE) film was prepared by radiation induced graft polymerization of an epoxy group containing monomer, glycidyl methacrylate (GMA) onto nonwoven PE fabric and subsequent chemical modification to IDA group. The effect of solvents (water, methanol, ethanol, isopropyl alcohol and dimethyl sulfoxide) on modification of epoxy group of GMA grafted PE (GMA-g-PE) fabric to IDA group was investigated. Ethanol provided a higher density of IDA group on GMA-g-PE fabric. Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis and dynamic mechanical analysis of IDA-GMA-PE adsorbent, GMA-g-PE fabric and pure PE fabric were studied. The ability of resultant IDA adsorbent to absorb chromium from aqueous medium was evaluated by batch method. The parameters such as feeding chromium concentration, pH of chromium solution and adsorption time of IDA adsorbent were discussed. The obtained results illustrate that the IDA adsorbent could be fruitful to absorb chromium from water. The equilibrium experimental data for the adsorption of chromium on IDA adsorbent fitted Langmuir isotherm model. [ABSTRACT FROM AUTHOR]

A new effective adsorbent was developed for a selective extraction and determination of lanthanum from aqueous media by use of inductively coupled plasma-optical emission spectrometry. The new adsorbent was based on activated carbon modified with Schiff’s base derived from diethylenetriamine and 3,4-dihydroxybenzaldehyde (AC-DETADHBA). Isotherm and kinetic models were systematically investigated to evaluate the analytical potential of the AC-DETADHBA phase toward La(III) by employing a batch adsorption technique. Surface properties of AC-DETADHBA were characterized by Fourier transform infrared spectrometry. The maximum static adsorption capacity was determined to be 144.80 mg g−1 at pH 6, providing that the adsorption capacity of La(III) was improved by 61.79% with the AC-DETADHBA phase as compared to the carboxylic acid derivative of activated carbon after only 1 h contact time. Adsorption isotherm results demonstrated that the adsorption process was mainly monolayer on a homogeneous adsorbent surface, confirming the validity of Langmuir adsorption isotherm model. Data obtained from kinetic models study indicated that the adsorption of La(III) onto the AC-DETADHBA phase obeyed a pseudo second-order kinetic model. In addition, results of thermodynamic investigation also revealed that the adsorption mechanism of AC-DETADHBA toward La(III) is a general spontaneous process and favorable. The effect of several coexisting metal ions displayed that the recovery of La(III) was not affected by the medium composition containing either individual or mixed metals. Finally, the newly proposed method gave satisfactory results for the determination of La(III) in environmental water samples.

In this research, the effect of the initial concentration of zirconium, nitric acid concentration, volume percentage of organic solvent phase (tributyl phosphate) and the phase ratio on extraction (%) was studied in a batch method and the optimum conditions for continuous operation (Mixer-settler) of these parameters were introduced. In the experimental studies of zirconium extraction in a 6-stage horizontal laboratory mixer-settler, the aqueous solution (feed) was 4 M nitric acid mixed with 4 M HCl containing 60 gr per liter of zirconium. 50%V tributyl phosphate in kerosene, 1000 rpm impeller speed, with the equal phase ratio at ambient temperature and pressure was used for the extraction operations. In this research work, the extraction of zirconium at settler stages within 3 different times has been compared with the theoretical quantities obtained from the McCabe curve. The zirconium extraction (%) at each stage of the mixer-settler was close to the corresponding amount in equilibrium conditions, indicating a very good agreement between theoretical and experimental data.

The rapid development of industrial sector gave not only positive impact on national income but also a negative impact on the environment. Iron (III) heavy metal ion is one of harmful metal ion for biotic creatures and human. In order to control the metal ion in wastewater, adsorption method was introduced. Andisol soil (AndS) containing allophane and sugar palm fiber (SPf) having cellulose are potential materials utilized as an adsorbent for iron metal ion removal in aqueous solution. In this study, the AndS/SPf composite was successfully fabricated and characterized as well as optimized as an adsorbent. The adsorption process was performed using a batch method by varying pH condition, calcination temperature, AndS:SPf ratio and contact time. This study showed that the optimum pH by 5, calcination temperature by 100 °C, AndS:SPf ratio by 1:3 and contact time by 45 minutes. This research also inform the isotherm adsorption, i.e. Langmuir and Freundlich model and found that the adsorption followed Freundlich model. [ABSTRACT FROM AUTHOR]

New nano chelating resin 2-amino pyridine−functionalized polyacrylonitrile (CPN-AP) (≈ 70 nm) was prepared by precipitation polymerization of acrylonitrile with N, N ′ -methylenebisacrylamide followed by treatment with 2-amino pyridine. The physicochemical properties of the nano chelating resin were characterized by FTIR, SEM, TEM, BET, XRD, thermal analysis and water regain (W%). Batch technique was used to estimate the effects of some factors that control the adsorption of Hg(II), Cd(II) and Cr(III) including pH, concentration, contact time and temperature. The maximum adsorption capacities at 25 °C were 3.3, 0.94 and 0.43 mmolg −1 resin for Hg(II), Cd(II) and Cr(III), respectively. The sorption kinetics and equilibrium data fitted well to the pseudo-second-order model and Langmuir isotherm model, respectively. The intraparticle diffusion model shows three-linear portions. Hence, more than one-step may control the adsorption process. Thermodynamic parameters at different temperatures (25, 35 and 45 °C) revealed that the adsorption of all metal ions was endothermic and (i) Hg(II) sorption was spontaneous (ii) Cd(II) sorption was non-spontaneous at 25 °C and spontaneous at 35 and 45 °C, (iii) Cr(III) sorption was non-spontaneous. Additionally, the removal of Hg(II) was studied using column method. Thomas and Yoon–Nelson models were applied to predict the breakthrough curves and to determine the characteristic parameters of the column that are helpful for process design at a real scale. The prepared nanoparticles were used successfully for six times. [ABSTRACT FROM AUTHOR]

The article presents a study which examines the effectiveness of newly synthesized polyethersulfones/Ag nanocomposites films as adsorbents for selective separation of 4-nitrophenol from environmental waters.

In the current study, a sensitive and simple method for selective separation of gold, Au(III), from water samples prior to its determination by inductively coupled plasma-optical emission spectrometry (ICP-OES), was investigated. The method utilized activated carbon modified with tris(hydroxymethyl)aminomethane (AC–TRIS) as a solid-phase extractant. Surface properties of the AC–TRIS phase were characterized by Fourier transform infrared (FT-IR) spectroscopy. The separation parameters for effective adsorption of Au(III), including effects of pH, Au(III) concentration, shaking time, and common coexisting ions were examined using batch method. The optimum pH value for the separation of Au(III) on the new sorbent was 1.0, and the maximum static adsorption capacity of Au(III) onto the AC–TRIS was 33.57 mg g−1 at this pH and after 1 h contact time. The Au(III) adsorption data were modeled using both Langmuir and Freundlich classical adsorption isotherms. Results demonstrated that the adsorption of Au(III) onto activated carbon followed second-order kinetic model. In addition, the efficiency of this methodology was confirmed by applying it to real environmental samples.

Iminodiacetate chelating resin (IDAR) was prepared for removal of heavy metal ions from aqueous media. The prepared resin showed a powerful uptake behavior toward Cu(II), Ni(II), Hg(II), and Co(II). Different experimental parameters such as solution pH, metal ions concentration, contact time, and adsorption temperature were studied in batch method. The maximum adsorption capacity was found to be 1.79, 1.72, 0.96, and 1.26 mmol/g resin for Cu(II), Ni(II), Hg(II), and Co(II), respectively. The experimental data were analyzed by Langmuir, Freundlich, and Temkin isotherm models. Equilibrium studies showed that the data of metal ions adsorption followed the Langmuir model. Also, the kinetic and thermodynamic parameters of the adsorption process were estimated. These parameters showed that the adsorption process is spontaneous and followed the pseudo-second-order kinetics. Additionally, the removal of metal ions using (IDAR) chelating resin has been studied using column technique as well. Elution of chelating resin loaded with Cu(II), Ni(II), and Hg(II) was successfully performed with 0.2 M HNO3solutions and the resin could be reused for five sorption–desorption cycles with small loss of adsorption capacity. Co(II) was partially eluted under these conditions and penetrated throughout the length of the column. [ABSTRACT FROM AUTHOR]

Heavy metal contamination has become a world concern with the rapid industrialization and urbanization process. In this study, a mesophile consortium including Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans and Leptospirillum ferriphilum was applied in metals' bioleaching with the assistance of isolated acid-tolerant microorganisms Rhodotorula and Aspergillus niger. The results showed that the bioleaching was totally inhibited in non-batch method system for the alkalinity and buffering capacity of the sediment. The inhibition on bioleaching can be effectively relieved with the batch method adopted. Dissolved organic matter hampered the substrate utilization and prolonged the bioleaching process. The toxic effect of dissolved organic matter to acidophile can be reduced by the isolated heterotrophic microorganism. A. thiooxidans was the dominant species in the early bioleaching stage, while the ratio of ferrous oxidation bacteria increased in the later stage. The introduction of heterotrophic microorganism to the system contributed to form a suitable ecological niche of each species. In the batch method adopted and heterotrophic microorganism inoculated system, the bioleaching efficiency of Mn, Cu, Zn and Cd reached 94, 90.9, 94.74 and 84.2 %, respectively. The main fractions of heavy metals after bioleaching are comparatively stable speciation. Heavy metals were reduced both in total content and bioavailability. [ABSTRACT FROM AUTHOR]

Stormwater biofilters must be validated before they can be a trusted component of the treatment train used for water supply augmentation. Currently, only in situ challenge testing is accepted for treatment validation, yet this is impractical for stormwater biofilters because of their size and operational conditions; e.g. stormwater harvesting biofilters are often large systems that receive significant volumes of urban stormwater during short periods of time. This study proposes an alternative validation tool for stormwater biofilters that uses a process-based model calibrated against in situ tracer and laboratory based data. The method is developed and tested using fluorescein as the reference micropollutant at two different biofilters: (i) a well-designed system that uses sand as filter media and has a submerged zone (S-SZ), and (ii) a system with loamy sand (with content of silt and clay well above best practice), which does not have a submerged zone (LS-noSZ). Firstly, a model that can simulate hydrodynamic and pollutant transport of micropollutants in stormwater biofilters was selected. In situ tracer tests and laboratory batch studies were then performed to derive the model parameters using soil samples collected from the two biofilters. Without further calibration, the model was applied to simulate a number of in situ fluorescein challenge tests performed on the biofilters. The modelled outflow concentrations were compared with the in situ measurements, showing that the proposed alternative validation method could provide reliable predictions of fluorescein removal in the S-SZ, with predicted outflow concentrations agreeable to the measured data (Nash Sutcliffe coefficient, E = 0.67). The peak outflow concentrations that are important for validation study were particularly well modelled; the differences between the modelled and measured peak values were −3.9% to +7.4% for spiking tests and −4.4% to 28% for flushing/rinsing tests. However, for LS-noSZ, the proposed tool did not work well ( E = −1.7), which was attributed to the fact that flow through this system could not be reliably modelled due to high silt and clay content in the soil. The differences of peak concentrations of LS-noSZ were between −3.6% (under-predicted) and +76% (over-predicted). [ABSTRACT FROM AUTHOR]