Evaluation of the Biosorption Characteristics of <Emphasis Type="Italic">Tremella fuciformis</Emphasis> for the Decolorization of Cationic Dye from Aqueous Solution

The present work reported on the evaluation of the methylene blue dye biosorption property of Tremella fuciformis under different experimental conditions. Batch mode experiments were carried out using different experimental parameters such as initial pH, dye concentration, biosorbent amount, contact time and temperature. Four widely used kinetic models were used to elucidate the biosorption kinetics. And the kinetic analysis illustrated that the experimental data best followed the pseudo-second-order kinetic model. Biosorption equilibrium was also investigated using four widely used isotherm models. The results indicated that the experimental equilibrium data fitted very well with Langmuir isotherm models. Thermodynamic analysis of biosorption processes was found to be feasibility, spontaneous and exothermic nature of MB biosorption. These results indicated that T. fuciformis would be a high effective and environmental friendly biosorbent for MB removal from aqueous solution.     

Poly(Acrylic Acid) Grafted Sodium Alginate Di-Block Hydrogels as Efficient Biosorbents; Structure-Property Relevance

Naturally-based poly(acrylic acid) grafted sodium alginate di-block hydrogels were investigated as high efficiency biosorbents for copper(II) ion. The grafted di-block hydrogel was characterized using FTIR, TGA and SEM techniques. Blank and immobilized algal biosorbent beads formed via 2.0% (w/w) calcium ions were also investigated. Batch adsorption experiments revealed optimal pH dependence of copper(II) ion biosorption at pH 5.5 with high efficient copper(II) ion uptake of 98.5 mg/g. The dynamics studies showed that the high efficiency copper(II) ion biosorption followed pseudo-second order kinetics with significant contribution of intraparticle diffusion mechanism. The equilibrium data fitted to Langmuir, Freundlich, and Dubinin–Radushkevich (D–R) adsorption isotherm models. Thermodynamics parameters for copper(II) biosorption on blank and immobilized algal beads depicted the spontaneous nature of the biosorption process. Such high efficiency, feasibility, simplicity, and low cost properties adapt the di-block biosorbent to be the next generation promising biosorbents for water decontamination and to help in the recovery of the missing ecologic harmony.     

Biosorption potential and kinetic studies of vegetable waste mixture for the removal of Nickel(II)

Biosorption potential of new low cost biosorbent prepared from vegetable waste, composed of 1:1 mixture of potato and carrot peels for the removal of Ni(II) from aqueous solution was determined. The residual metallic ion concentrations were determined using an atomic absorption spectrophotometric technique (AAS). Batch experiments were conducted to optimize parameters such as initial pH, temperature, contact time, initial metal ion concentration and biosorbent dose and the results showed that maximum adsorption of Nickel (79.32 %) occurs when the contents were stirred for 75 min with 3.0 g of biosorbent at 35 °C and pH 4. Kinetic studies of the reaction revealed that it follows a pseudo-second order reaction. The experimental results were analyzed in terms of Langmuir and Freundlich isotherms. The Langmuir isotherm model fits well to data of Ni(II) biosorption by the prepared biomass as compared to the model of Freundlich. Both neat and Ni loaded biosorbent samples were analyzed by AAS using a dry ashing process in a furnace and also by use of a FT-IR spectrophotometer and an X-Ray florescence spectrometer in order to confirm the biosorption of Ni(II) and the results have revealed that a significant amount of Ni is present in the spent biosorbent.     

Biosorption of Hg(II) Ions From Aqueous Solution Using the Aquatic Weed Water Hyacinth With Equilibrium and Kinetic Modeling

The potential for biosorption of Hg(II) ions from aqueous solutions using water hyacinth was studied. The effect of the retention period (0, 1, 3, 7, and 15 days), pH (3, 5, 7, and 9), initial concentration of Hg(II) ions (5, 10, and 15 mg/L), and organic loading rate (25, 50, and 75 percent) on biosorption were investigated. The physicochemical parameters were also analyzed at various concentrations of Hg(II) ions before and after treatment. The maximum biosorption rate was obtained at 15 days with the initial concentration of 10 mg/L at a pH of 7 and organic loading rate of 50 percent. The maximum biosorption capacity of both water hyacinth roots and shoots were 5.5 mg/L and 3.8 mg/L, respectively. The Hg(II) biosorption data were analyzed using the first‐ and second‐order kinetic models. Pseudo second‐order kinetics was considered the most appropriate model for predicting the biosorption capacity of both water hyacinth roots and shoots, and the modeled results were compared to the experimental results. Langmuir and Freundlich isotherms were used to evaluate the experimental data, and their constants were derived. Biosorption equilibrium data were best described by the Langmuir isotherm model followed by the Freundlich model. © 2013 Wiley Periodicals, Inc.     

固定化海带生物吸附剂的制备及其吸附Ni~(2+)的动力学特性

以海藻酸钠、明胶和海带粉为原料制备了固定化海带生物吸附剂。固定化海带生物吸附剂对Ni2+的吸附过程可分为3个阶段:快速吸附阶段、缓慢吸附阶段和吸附平衡阶段。动力学过程可用Lagergren准二级反应动力学方程描述,限速步骤为化学吸附。随Ni2+初始质量浓度的增加,固定化海带生物吸附剂的Ni2+吸附量逐渐增大,Ni2+去除率逐渐降低。吸附过程符合Langmuir和Freundlich吸附等温方程,说明该吸附体系既有物理吸附又有化学吸附,从吸附状态看属于多层吸附,由Langmuir吸附等温方程得出固定化海带生物吸附剂对Ni2+的最大吸附量为39.43mg/g,说明固定化海带生物吸附剂对Ni2+有较好的吸附性能。     

A comparative adsorption/biosorption study of mono-chlorinated phenols onto various sorbents

The potential use of dried activated sludge and fly ash as a substitute for granular activated carbon for removing mono-chlorinated phenols (o-chlorophenol and p-chlorophenol) was examined. The pollutant binding capacity of the adsorbent/biosorbent was shown to be a function of substituted group, initial pH and initial mono-chlorinated phenol concentration. The working sorption pH value was determined as 1.0 and the equilibrium uptake increased with increasing initial mono-chlorinated phenol concentration up to 500 mg dm(-3) for all the mono-chlorinated phenol-sorbent systems. The suitability of the Freundlich, Langmuir and Redlich-Peterson adsorption models to the equilibrium data were investigated for each mono-chlorinated phenol-sorbent system. The results showed that the equilibrium data for all the mono-chlorinated phenol-sorbent systems fitted the Redlich-Peterson model best within the concentration range studied.     

改性生物炭对Ni~(2+)和Cu~(2+)的吸附

以废弃松木屑为原料制备了生物炭,采用六亚甲基四胺(HMTA)和/或CO2对其进行改性,并将其用于水中Ni2+和Cu2+的吸附。表征结果显示,以HMTA和CO2共同改性的生物炭BC1的表面积最小但表面含氧官能团含量最高。实验结果表明:生物炭经改性后,其吸附性能明显提高,且以BC1为最优;在不调节溶液p H、初始重金属离子质量浓度为50 mg/L、吸附剂加入量分别为2.0 g/L和1.0 g/L、吸附时间分别为360 min和240 min的优化条件下,BC1对Ni2+和Cu2+的去除率分别达到99.81%和95.88%;改性生物炭对Ni2+和Cu2+的吸附过程可以用Langmuir等温吸附模型来描述,而其吸附动力学具有拟二级动力学方程特征。     

生物炭对铅离子的吸附性能

以废弃松木屑为原料,采用控制热分解法制备了生物炭。运用BET和FTIR等技术对生物炭进行了表征,考察了生物炭对铅离子的吸附效果,并探讨了吸附机理。表征结果显示,700℃氨气处理的生物炭,其比表面积和总孔体积显著增大。实验结果表明:生物炭对铅离子的吸附效果优于普通活性炭,且以700℃氨气处理的生物炭为最佳;随溶液pH的升高生物炭对铅离子的去除率增大,当pH为4~6时去除效果较好;在溶液pH为6、初始铅离子质量浓度为50 mg/L、吸附剂加入量为1 g/L、吸附时间为6 h的条件下,700℃氨气处理的生物炭对铅离子的去除率达99%以上;700℃氨气处理的生物炭的Langmuir吸附常数和Freundlich吸附常数远大于普通活性炭和其他工艺的生物炭;铅离子在生物炭上的吸附过程符合拟二级动力学方程。     

Mercury removal from aqueous solutions by zinc cementation

The main purpose of this research is to study the addition effect of the surfactant and other operating factors on the treatment of wastewater containing mercury ions in aqueous solution by cementation with sacrificing metal, zinc. The removal of mercury ions from aqueous solutions by cementation of zinc powder was found to be a function of solution pH and temperature, amount of zinc, concentration of mercury ion, contact time and the addition of several organic surfactants. Cementation of mercury was shown to be a feasible process to achieve a very high degree of mercury removal over a broad operational range within a fairly reasonable contact time. The reaction rate is approximately first order with respect to the concentration of mercury ion in aqueous solution. Among the surfactants used in this study, only the presence of SDS, an anionic surfactant, slightly enhanced the cementation rate of mercury. The presence of CTAB and Triton-X100 retarded the cementation of mercury by zinc.     

Eco-Friendly, Vascular Shape and Interpenetrating Poly (Acrylic Acid) Grafted Pectin Hydrogels; Biosorption and Desorption Investigations

The synthesis and characterization of poly (acrylic acid) grafted pectin hydrogel followed by biosorption and desorption characteristics of cadmium, as a model heavy metal, have been studied. The grafted eco-friendly pectin based interpenetrating hydrogel was prepared in the presence of gluteraldehyde crosslinker under N₂ atmosphere and characterized using ¹H-NMR, FTIR, TGA and SEM techniques. Gluteraldehyde was found to form one-arm and two-arm crosslinks in the copolymer. Upon grafting, two-dimensional sheet structures bounded to tubular and vascular cylindrical rods were observed. The biosorption and desorption data, determined experimentally, were fitted to pseudo-second order reaction kinetics. At higher ionic strength values, the maximum metal uptake value (q _max) was lowered and pseudo-second order rate constant (k ₂) was increased. Whereas, at higher pH values the maximum metal uptake value (q _max) was increased and Pseudo-second order rate constant (k ₂) was decreased. 0.1?M HCl solution was a suitable eluent to regenerate the hydrogel surface and recover the adsorbed cadmium metal ions. Pectin based copolymer could be used as an efficient candidature biosorbent for the recovery of cadmium metal ions from aqueous solutions.     

Biosorption of Malachite Green from Aqueous Solutions onto Polylactide/Spent Brewery Grains Films: Kinetic and Equilibrium Studies

Batch experiments were conducted to study the biosorption of Malachite Green (MG) onto polylactide (PLA)/spent brewery grains (SBGs) films. Films were prepared by solvent-casting method using dichloromethane. Effects of contact time, pH, salt concentration, and optimal experimental condition was evaluated. At pH 6.89 and low salt concentration, Malachite Green was removed effectively. The isotherm data fitted the Freundlich model with 0.969 R² value and 0.738 slope implying chemisorptions process. The biosorption process followed pseudo-second order kinetics with calculated adsorption capacity at equilibrium (qe) of 0.572?mg/g at 23?°C. The investigation showed that PLA/SBGs films are effective in dye removal from textile, paper and leather industries effluents.     

硝酸改性活性炭的制备及其对Cr（Ⅵ）

利用硝酸对颗粒活性炭进行改性，处理含铬废水，并考察了吸附时间、溶液pH、吸附剂加入量对改性活性炭吸附Cr（Ⅵ）效果的影响。实验结果表明：经过硝酸氧化改性的活性炭比表面积有所增加，官能团总量增加明显；吸附剂对Cr（Ⅵ）的去除率随振荡时间的增加而增加；对于质量浓度为10mg/L的100mLCr（Ⅵ）溶液，当溶液pH为中性，30%（体积分数）硝酸改性的颗粒活性炭的加入量为0.4g，其对Cr（Ⅵ）的最大去除率为98%。     

Effective bioremoval of Fe(III) ions using paprika (Capsicum annuum L.) pomace generated in the food industry

In these studies, removal of Fe(III) ions by biosorption processes from aqueous solutions was carried out using paprika (Capsicum annuum L.) pomace generated during processing in the food industry. The biosorbent material was characterized using several analytical methods, including particle size distribution, XRD, SEM–EDS, electrokinetic zeta potential, surface area analysis (BET, BJH), thermogravimetry, morphology (SEM), spectrophotometry FT-IR. Several factors, such as biosorbent dosage, initial concentration, contact time and initial pH were analyzed to show an effect on the bioremoval process, efficiency and adsorption capacity. As a result, the maximum adsorption efficiency and capacity were determined to be 99.1% and 7.92 mg/g, respectively. Based on the kinetics analysis, the bioremoval process is better described by the Langmuir isotherm model and the pseudo-second order equation model. In conclusion, the achieved research results suggest that paprika biomass can be an effective material for efficiently removing iron(III) from wastewater and improving water quality. These studies on the recovery of iron metal from the environment fit in the latest trends in the concept of the global circular economy.

     

Removal of Cr(VI) Ions from Aqueous Solutions Using Poly 3-Methyl Thiophene Conducting Electroactive Polymers

This paper deals with a new application of poly 3-methyl thiophene synthesized chemically onto sawdust (termed as P3MTh/SD) as an effective adsorbent for removal of Cr(VI) ions from aqueous solutions using column system. Chemical synthesis of poly 3-methyl thiophene was performed by addition of ferric chloride (in chloroform) as oxidant to sawdust which had previously been soaked in monomer solution. All the sorption experiments were conducted using dynamic or column system at room temperature. The effect of important parameters such as pH and initial concentration on uptake of Cr(VI) was investigated. In order to find out the possibility of the regeneration and reuse of the exhausted adsorbent, desorption studies were also performed. The currently introduced adsorbent was found to be an efficient adsorbent for removal of highly toxic and hazardous Cr(VI) ions from aqueous solutions. As our breakthrough analysis has indicated, each gram of P3MTh/SD is able to remove more than 95% of Cr(VI)ions from 300 mL of Cr(VI) polluted solution with the initial concentration of 25 mg L⁻¹ in column system. Sorption/desorption of Cr(VI) ions was found to be a highly pH dependent processes.     

PP-g-GMA-DETA螯合纤维吸附处理含Pb2+废水

采用低温等离子体技术将甲基丙烯酸缩水甘油酯（GMA）接枝在聚丙烯（PP）纤维表面,再用二乙烯三胺（DETA）胺化,制得PP-g-GMA-DETA螯合纤维,并应用于含铅模拟废水的处理。考察了吸附时间、溶液pH和初始Pb²⁺质量浓度对吸附量的影响。实验结果表明：PP-g-GMA-DETA螯合纤维对Pb²⁺的吸附速率很快,15 min时基本达到平衡吸附量,约为24.83 mg/g;随溶液pH的增加吸附量先迅速升高后保持平稳,在溶液pH为5.0时达到25.37 mg/g;随初始 Pb²⁺质量浓度的增加,吸附量迅速上升,当初始Pb²⁺质量浓度达到60 mg/L后,吸附量增长缓慢,最终保持吸附平衡。PP-g-GMA-DETA螯合纤维对Pb²⁺的吸附符合Langmuir等温吸附模型,是典型的单分子层吸附,饱和吸附量为31.40 mg/g。     

氨基改性二氧化硅气凝胶的制备及其对镍离子的吸附性能

以正硅酸乙酯为硅源、3-氨丙基三乙氧基硅烷为改性剂,采用溶胶-凝胶法制备了氨基改性二氧化硅气凝胶,采用FTIR、SEM、TEM和BET技术对其进行了表征,并将其用于对水中镍离子的吸附。表征结果显示,改性前后的气凝胶均具有三维多孔网络结构,比表面积分别为877.35 m²/g和357.76 m²/g,平均孔径分别为10 nm和12 nm。实验结果表明：溶液pH为4~7时改性气凝胶对镍离子均保持较高的吸附量,溶液pH为6左右时吸附量最高;Langmuir等温吸附模型能更好地描述镍离子在改性气凝胶上的吸附行为,其饱和吸附量为70.03 mg/g,改性前仅为29.05 mg/g;改性气凝胶重复使用5次后,仍保持较高的镍离子去除率,重复使用性能良好。     

Enzyme-Assisted Extraction and Pb<Superscript>2+</Superscript> Biosorption of Polysaccharide from <Emphasis Type="Italic">Cordyceps militaris</Emphasis>

The enzyme assisted extraction conditions of polysaccharide from Cordyceps militaris mycelia were firstly investigated by kinetics analysis and the optimal operating was found to be: extraction temperature 40 °C; solid-solvent ratio 1:20; extraction pH 4.0; cellulase concentration 2.0%. The polysaccharide extraction yield was 5.99% under these optimized conditions. Furthermore, a fundamental investigation of the biosorption of Pb²⁺ from aqueous solution by the C. militaris polysaccharide was performed under batch conditions. The suitable pH (5.0), polysaccharide concentration (0.20 g L^?1), initial Pb²⁺ concentration (300 mg L^?1) and contact time (40 min) were outlined to enhance Pb²⁺ biosorption from aqueous medium. The Langmuir isotherm model and pseudo first order kinetic model fitted well to the data of Pb²⁺ biosorption, suggesting the biosorption of Pb²⁺ onto C. militaris polysaccharide was monolayer biosorption and physical adsorption might be the rate-limiting step that controlled the adsorption process. FTIR analysis showed that the main functional groups of C. militaris polysaccharide involved in adsorption process were carbonyl, carboxyl, and hydroxyl groups.     

Activated carbon from Ceiba pentandra hulls, an agricultural waste, as an adsorbent in the removal of lead and zinc from aqueous solutions

The ability of low-cost activated carbon prepared from Ceiba pentandra hulls, an agricultural waste material, for the removal of lead and zinc from aqueous solutions has been investigated. In the batch tests experimental parameters were studied, including solution pH, contact time, adsorbent dose and initial metal ions concentration. The adsorbent exhibited good sorption potential at pH 6.0. Maximum removal of lead (99.5%) and of zinc (99.1%) with 10 g/l of sorbent was observed at 50 mg/L sorbate concentration. Removals of about 60-70% occurred in 10 min, and equilibrium was attained at around 50 min for both metals. The functional groups (CO, SO,-OH) present on the carbon surface were responsible for the adsorption of metal ions. The adsorption parameters were analysed using both the Freundlich and Langmuir models. The data are better fitted by the Freundlich isotherm as compared to Langmuir model, and the adsorption capacities for lead and zinc were 25.5 and 24.1 mg/g, respectively. Kinetics of adsorption obeyed a second order rate equation and the rate constant was found to be 2.71 x 10(-2) and 2.08 x 10(-2) g/mg/min for lead and zinc, respectively. The desorption studies were carried out using dilute HCl, and the effect of HCl concentration on desorption was studied. Maximum desorptions of 85% for lead and 78% for zinc were attained with 0.15 M HCl.     

Biosorption of copper from aqueous solutions utilizing agricultural wastes

The purpose of this study was to determine the copper (Cu) biosorption capacities of several agricultural wastes from aqueous solutions. Samples of agricultural wastes were tested unaltered and after hydrochloric acid (HCl) treatment. Additional parameters tested include sample dose, contact time, particle size, mixing temperature, and the concentrations and pH of the Cu solutions. Desorption studies were performed to determine if the removed Cu could be recovered. In addition, tests were conducted to determine if the agricultural waste samples (AWS) could be reused for additional Cu biosorption cycles. The results of this study demonstrate a wide range of Cu biosorption proficiencies ranging from 0% to 100% removal. The parameters that resulted in higher Cu removal include higher pH and lower Cu solution concentration. Desorption results showed a 58% to 86% Cu recovery rate. Three of the five reused AWS were effective at removing Cu during subsequent trials. Therefore, these AWS types can be reused for additional Cu biosorption cycles. Hence, it is possible that using those AWS for metal treatment could reduce hazardous waste disposal inefficiencies and costs by avoiding disposing of spent AWS following each Cu biosorption cycle.