Feasibility of using <Emphasis Type="Italic">Trichoderma harzianum</Emphasis> biomass for the removal of erioglaucine from aqueous solution

The test fungus Trichoderma harzianum was isolated from the Western Ghats area of Tamilnadu, India. The study involves the feasibility of using T.harzianum to remove erioglaucine from an aqueous solution in batch mode. The batch mode experimental parameters such as effect of agitation time and initial dye concentration, adsorbent mass and pH were determined. The results revealed that, the fungal biomass at 1.5 g/50 ml adsorbent mass removed 75.67–88.05% of dye (10–50 mg/l) in 105 min at pH 4.0. The adsorption equilibrium data followed both Langmuir and Freundlich isotherms. From the Langmuir isotherm, the adsorbent had adsorption capacity (Q ₀ ) of 3.09 mg/g. Pseudo first and second order rate kinetic equations were applied to the experimental adsorption data. The results indicate that the adsorbent system followed second order rate kinetics.     

Biosorption of Lead from Industrial Wastewater Using Chrysophyllum albidum Seed Shell

The shell of the seed of Chrysophyllum albidum carbon was used to adsorb lead (Pb) from aqueous solution, the sorption process with respect to its equilibria and kinetics as well as the effects of pH, contact time, adsorbent mass, adsorbate concentration, and particle size on adsorption were also studied. The most effective pH range was found to be between 4.5 and 5 for the sorption of the metal ion. The first-order rate equation by Lagergren was tested on the kinetic data and the adsorption process followed first-order rate kinetics. Isotherm data were analyzed for possible agreement with the Langmuir and Freundlich adsorption isotherms; the Freundlich and Langmuir models for dynamics of metal ion uptake proposed in this work fitted the experimental data reasonably well. However, equilibrium sorption data were better represented by Langmuir model than Freundlich. The adsorption capacity calculated from Langmuir isotherm was 72.1 mg Pb (II) g^{- 1} at initial pH of 5.0 at 30°C for the particle size of 1.00 to 1.25 mm with the use of 2.0 g/100 ml adsorbent mass. The structural features of the adsorbent were characterized by Fourier transform infrared (FTIR) spectrometry; the presence of hydroxyl, carbonyl, amide, and phosphate groups confirms the potential mechanism adsorption of the adsorbent. This readily available adsorbent is efficient in the uptake of Pb (II) ion in aqueous solution, thus, it could be an excellent alternative for the removal of heavy metals and organic matter from water and wastewater.     

Caffeine adsorption of montmorillonite in coffee extracts

The growth in health-conscious consumers continues to drive the demand for a wide variety of decaffeinated beverages. We previously developed a new technology using montmorillonite (MMT) in selective decaffeination of tea extract. This study evaluated and compared decaffeination of coffee extract using MMT and activated carbon (AC). MMT adsorbed caffeine without significant adsorption of caffeoylquinic acids (CQAs), feruloylquinic acids (FQAs), dicaffeoylquinic acids (di-CQAs), or caffeoylquinic lactones (CQLs). AC adsorbed caffeine, chlorogenic acids (CGAs) and CQLs simultaneously. The results suggested that the adsorption selectivity for caffeine in coffee extract is higher in MMT than AC. The caffeine adsorption isotherms of MMT in coffee extract fitted well to the Langmuir adsorption model. The adsorption properties in coffee extracts from the same species were comparable, regardless of roasting level and locality of growth. Our findings suggest that MMT is a useful adsorbent in the decaffeination of a wide range of coffee extracts.     

Preparation,Characterization and Application of Magnetic Fe3O4-CS for the Adsorption of Orange I from Aqueous Solutions

Fe₃O₄ (Fe₃O₄-CS) coated with magnetic chitosan was prepared as an adsorbent for the removal of Orange I from aqueous solutions and characterized by FTIR, XRD, SEM, TEM and TGA measurements. The effects of pH, initial concentration and contact time on the adsorption of Orange I from aqueous solutions were investigated. The decoloration rate was higher than 94% in the initial concentration range of 50–150 mg L⁻¹ at pH 2.0. The maximum adsorption amount was 183.2 mg g⁻¹ and was obtained at an initial concentration of 400 mg L⁻¹ at pH 2.0. The adsorption equilibrium was reached in 30 minutes, demonstrating that the obtained adsorbent has the potential for practical application. The equilibrium adsorption isotherm was analyzed by the Freundlich and Langmuir models, and the adsorption kinetics were analyzed by the pseudo-first-order and pseudo-second-order kinetic models. The higher linear correlation coefficients showed that the Langmuir model (R² = 0.9995) and pseudo-second-order model (R² = 0.9561) offered the better fits.     

Adsorption of Methyl Parathion from Aqueous Solutions Using Mango Kernels: Equilibrium,Kinetic and Thermodynamic Studies

The adsorption of methyl parathion from aqueous solutions by the low-cost and abundant adsorbent mango kernel was studied in a batch adsorption system. The adsorption was studied as a function of pH, contact time, initial pesticide concentration, adsorbent dose, and temperature. A maximum adsorption of 98% ± 1% was achieved. Physicochemical characterization of the adsorbent was carried out by EDXRF, BET, and CHNS analysis. Freundlich, Langmuir, and Dubinin-Radushkevich isotherms were employed to evaluate the adsorption capacity of the adsorbent. Lagergren, Morris-Weber, and Reichenberg equations were employed to study the kinetics of the adsorption process. Thermodynamic parameters Δ H, Δ S, and Δ G were computed. The developed adsorption method was applied to real environmental samples.     

Highly enhanced adsorption for decontamination of lead ions from battery wastewaters using chitosan functionalized with xanthate

Decontamination of lead ions from aqueous media has been investigated using cross linked xanthated chitosan (CMC) as an adsorbent. Various physico-chemical parameters such as contact time, amount of adsorbent, concentration of adsorbate were optimized to simulate the best conditions which can be used to decontaminate lead from aqueous media using CMC as an adsorbent. The atomic absorption spectrometric technique was used to determine the distribution of lead. Maximum adsorption was observed at both pH 4 and 5. The adsorption data followed both Freundlich and Langmuir isotherms. Langmuir isotherm gave a saturated capacity of 322.6+/-1.2mg/g at pH 4. From the FTIR spectra analysis, it was concluded that xanthate and amino group participate in the adsorption process. The developed procedure was successfully applied for the removal of lead ions from real battery wastewater samples.     

Scavenging Rhodamine B dye using moringa oleifera seed pod

Moringa oliferia seed pod was modified using orthophosphoric acid (H₃PO₄) and used as adsorbent for sequestering Rhodamine B (Rh-B) dye from aqueous solution. The acid-modified adsorbent (MOSPAC) was characterized using Scanning Electron microscopy (SEM), Fourier Transform Infra Red (FTIR), Energy Dispersive X-ray (EDX), pH point of zero charge (pH_pzc) and Boehm Titration (BT) techniques, respectively. Operational parameters such as contact time, initial dye concentration, adsorbent dosage, pH and solution temperature were studied in batch process. Optimum dye adsorption was observed at pH 3.01. Equilibrium adsorption data was tested data using four different isotherm models: Langmuir, Freundlich, Temkin and Dubinin-Radushkevich. Langmuir isotherm model fitted most with maximum monolayer adsorption capacity of 1250 mg g^–1. Pseudo-second-order kinetic model provided the best correlation for the experimental data. Thermodynamic study showed that the process is endothermic, spontaneous and feasible. MOSPAC is an effective adsorbent for the removal of RhB dye from aqueous solutions.     

Application of dye-ligands affinity adsorbent in capturing of rabbit immunoglobulin G

The applicability of dye-ligands attached to an expanded bed chromatography quartz base matrix (Streamline™) for the affinity bioseparation of rabbit immunoglobulin G (IgG) was investigated. Reactive Green 5 (RG-5) immobilized onto adsorbent was selected for capturing of rabbit-IgG due to its higher binding capacity compared to other dye-ligands possessing similar ligand density. Adsorption parameters such as pH, temperature, ionic strength and initial rabbit-IgG concentration were optimized for the adsorption of rabbit-IgG on the RG-5-immobilized adsorbent. The highest rabbit-IgG adsorption was recorded in pH 7.0, while the maximum binding capacity for BSA was achieved at pH 4.0. The adsorption of rabbit-IgG on RG-5-immobilized adsorbent was declined as the increase of ionic strength. There is no significant influence of temperature against adsorption efficiency of RG-5-immobilized adsorbent for rabbit-IgG. The adsorption phenomenon of rabbit-IgG on RG-5-immobilized adsorbent appeared to follow the Langmuir–Freundlich adsorption isotherm model. The theoretically maximum binding capacity (q_m) of RG-5-immobilized adsorbent estimated from this isotherm was 49.3 mg ml⁻¹, which is very close to that obtained experimentally (49.0 mg ml⁻¹). About 50% of bound BSA on RG-5-immobilized adsorbent in binary adsorption system was removed with washing buffer containing 1 M NaCl.     

Study on the removal of pesticide in agricultural run off by granular activated carbon

In this batch study, the adsorption of malathion by using granular activated carbon with different parameters due to the particle size, dosage of carbons, as well as the initial concentration of malathion was investigated. Batch tests were carried out to determine the potential and the effectiveness of granular activated carbon (GAC) in removal of pesticide in agricultural run off. The granular activated carbon; coconut shell and palm shells were used and analyzed as the adsorbent material. The Langmuir and Freundlich adsorption isotherms models were applied to describe the characteristics of adsorption behavior. Equilibrium data fitted well with the Langmuir model and Freundlich model with maximum adsorption capacity of 909.1 mg/g. The results indicate that the GAC could be used to effectively adsorb pesticide (malathion) from agricultural runoff.     

Experimental and kinetic studies on methylene blue adsorption by coir pith carbon

Varying the parameters such as agitation time, dye concentration, adsorbent dose, pH and temperature carried out the potential feasibility of thermally activated coir pith carbon prepared from coconut husk for removal of methylene blue. Greater percentage of dye was removed with decrease in the initial concentration of dye and increase in amount of adsorbent used. Kinetic study showed that the adsorption of dye on coir pith carbon was a gradual process. Lagergren first-order, second-order, intra particle diffusion model and Bangham were used to fit the experimental data. Equilibrium isotherms were analysed by Langmuir, Freundlich, Dubnin-Radushkevich, and Tempkin isotherm. The adsorption capacity was found to be 5.87 mg/g by Langmuir isotherm for the particle size 250-500 microm. The equilibrium time was found to be 30 and 60 min for 10 and 20 mg/L and 100 min for 30, 40 mg/L dye concentrations, respectively. A maximum removal of 97% was obtained at natural pH 6.9 for an adsorbent dose of 100 mg/50 mL and 100% removal was obtained for an adsorbent dose of 600 mg/50 mL of 10 mg/L dye concentration. The pH effect and desorption studies suggest that chemisorption might be the major mode of the adsorption process. The change in entropy (DeltaS0) and heat of adsorption (DeltaH0) of coir pith carbon was estimated as 117.20 J/mol/K and 30.88 kJ/mol, respectively. The high negative value of change in Gibbs free energy indicates the feasible and spontaneous adsorption of methylene blue on coir pith carbon.     

Removal of molybdate from water by adsorption onto ZnCl2 activated coir pith carbon

Removal and recovery of molybdate from aqueous solution was investigated using ZnCl2 activated carbon developed from coir pith. Studies were conducted to delineate the effects of contact time, adsorbent dose, molybdate concentration, pH and temperature. Two theoretical adsorption isotherms, namely, Langmuir and Freundlich were used to describe the experimental results. The Langmuir adsorption capacity (Q0) was found to be 18.9 mg molybdate/g of the adsorbent. Adsorption followed second order kinetics. Studies were performed at different pH values to find out the pH at which maximum adsorption occurred. The pH effect and desorption studies showed that ion exchange and chemisorption mechanism were involved in the adsorption process. Thermodynamic parameters such as DeltaG0, DeltaH0 and DeltaS0 for the adsorption were evaluated. Effect of foreign ions on adsorption of molybdate has been examined. The results showed that ZnCl2 activated coir pith carbon was effective for the removal and recovery of molybdate from water.     

Preparation of poly(methyl methacrylate)–grafted Hyparrhenia hirta for methyl red removal from colored solutions

Poly(methyl methacrylate)–grafted Hyparrhenia hirta (PMMA-g-Hh) biopolymer was prepared through radical polymerization using potassium persulfate (KPS) and applied in adsorption of methyl red from colored solutions. Solvent amount, initiator concentration, monomer concentration, temperature, and reaction time were the reaction parameters investigated for grafting. The biopolymer was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and x-ray diffraction spectroscopy (XRD). The adsorption process was investigated with respect to pH, contact time, initial concentration, adsorbent dosage, and temperature. The optimum adsorption parameters were pH 6, contact time 90 min, adsorbent dosage 0.6 g, and initial concentration 50 mg/L. The Langmuir adsorption model best fitted the adsorption process, with maximum adsorption capacities of 19.95, 6.89, and 4.02 mg/g at adsorbent dosages of 0.2, 0.6, and 1.0 g, respectively. The pseudo-second-order model described the kinetics data better. The adsorption process was physical, spontaneous, and endothermic. The adsorbent was still active after 10 adsorption-desorption cycles, showing its suitability for use in colored solutions treatment.     

One-pot synthesis and characterization of cross-linked quaternized chitosan microspheres as protein adsorbent

The one-pot synthesis and characterization of cross-linked quaternized chitosan microspheres (CQCM) as a protein adsorbent are presented. First of all, chitosan particles were prepared by spray drying method, and then they were quaternized and cross-linked in turn with glycidyltrimethylammonium (GTMAC) chloride and glutaraldehyde in isopropanol containing 10% water in one-pot. The effect of the reaction temperature, reaction time and the amounts of added GTMAC and glutaraldehyde on the protein adsorption ability of CQCM was investigated. The adsorption behavior of the CQCM prepared in the optimum synthetic conditions was well described by the Langmuir isotherm with maximum adsorption capacity equal to 1424 mg BSA/g dry weight. The particle size ranged from 7.6 to 48.9 μm. The mechanism of adsorption-desorption of BSA to the CQCM was ion-exchange. Finally, the extraction of soybean peroxidase from crude soybean peroxidase solution using the CQCM was performed.     

Adsorption of Methylene Blue Dye on Pure and Carbonized Water Weeds

The influence of process variables in batch adsorption has been used to assess the removal of methylene blue dye from aqueous solution using pure and carbonized biomasses of water hyacinth and water spinach. Dried leaves of the water weeds were carbonized at temperature up to 750°C. The optimum removal of dye was achieved at pH 10, 30°C, and 55 min at a dye concentration of 10 mg/L. In an attempt to describe the adsorption process, the equilibrium isotherm for each adsorbent was determined using Langmuir and Freundlich adsorption isotherm models. Maximum adsorption capacities based on the Langmuir model for pure and carbonized water hyacinth were (mg/g) 7.05 and 2.07, respectively, whereas those of pure and carbonized water spinach were 1.25 and 5.32, respectively. It was observed that the equilibrium data were well fit by both the Freundlich and Langmuir isotherms as R ² > .97. This study demonstrates that the two waterweeds are effective, environmentally friendly, and inexpensive biomaterials for the removal of color from industrial effluents.     

橘子皮对水中亚甲蓝的吸附性能

用低值廉价的橘子皮作为吸附剂对亚甲蓝染料废水进行吸附研究,考察了吸附平衡时间、溶液pH、染料浓度等因素对亚甲蓝吸附的影响,橘子皮主要含有羧基、氨基和磺酸基,橘子皮生物吸附剂对MB的吸附所需平衡时间为1小时,在pH=10的条件下,生物吸附剂对MB的最大吸附量(qm)为370.3±31.0 mg/g,等温吸附线符合Langmuir和Freundlich模式,研究结果表明：橘子皮对染料废水的吸附只需很短的时间则可达到吸附饱和,且吸附量大,具有很好的应用前景。     

Removal of hexavalent chromium using distillery sludge

Batch mode experiments were conducted to study the removal of hexavalent chromium from aqueous and industrial effluent using distillery sludge. Effects of pH, contact time, initial concentration and adsorbent dosage on the adsorption of Cr(VI) were studied. The data obeyed Langmuir and Freundlich adsorption isotherms. The Langmuir adsorption capacity was found to be 5.7 mg/g. Freundlich constants K(f) and n were 2.05 [mg/g(L/mg)(n)] and 3.9, respectively. Desorption studies indicated the removal of 82% of the hexavalent chromium. The efficiency of adsorbent towards the removal of chromium was also tested using chromium-plating wastewater.     

Efficient removal of both cationic and anionic dyes from aqueous solutions using a novel amphoteric straw-based adsorbent

In the current paper, a novel amphoteric straw-based adsorbent was prepared and applied to adsorb various dyes from aqueous solutions. The amphoteric adsorbent was proven effective in eliminating both cationic and anionic dyes (methylene blue and acid green 25), especially at corresponding favored pH conditions. The fundamental adsorption behavior of the adsorbent on removing various dyes was also investigated at different temperatures. The adsorption isotherms were all best-fitted by the Langmuir equation, whereas the adsorption kinetics was well-described by both the pseudo-second order model and the Elovich model. The experimental result revealed that the adsorption mechanism followed the monolayer chemical adsorption with an ion-exchange process.     

Removal of emulsified food and mineral oils from wastewater using surfactant modified barley straw

Barley straw, an agricultural waste, was chemically modified and evaluated for the removal of emulsified oils from aqueous solution. The chemical modification was performed using NaOH and a cationic surfactant, hexadecylpyridinium chloride monohydrate (CPC). The surface textural and chemical properties of the surfactant modified barley straw (BMBS) were characterized by N₂ adsorption, FT-IR, SEM and water soluble mineral content. The adsorption tests were carried out in batch adsorption system for removal of standard mineral oil (SMO) and canola oil (CO) from water. For both emulsified oils in wastewater, adsorption was found to be strongly related with solution pH. The isotherm study indicated that emulsified oil adsorption on BMBS could be fitted well with the Langmuir model other than Freundlich model. The maximum adsorption capacity for CO and SMO at 25 °C determined from the Langmuir isotherm is 613.3 and 584.2 mg g⁻¹, respectively. Desorption tests in water solution show that oil is strongly bonded with adsorbent and desorption is only about 1–2% in 24 h.