Reports are available on silver binding capacity of some microorganisms. However, reports on the equilibrium studies on biosorption of silver by macrofungi are seldom known. The present study was carried out in a batch system using dead biomass of macrofungus Pleurotus platypus for the sorption of Ag(I). P. platypus exhibited the highest silver uptake of 46.7 mg g(-1) of biomass at pH 6.0 in the presence of 200 mg L(-1) Ag(I) at 20°C. Kinetic studies based on fractional power, zero order, first order, pseudo-first order, Elovich, second order and pseudo-second order rate expressions have been carried out. The results showed a very good compliance with the pseudo-first order model. The experimental data were analyzed using two parameter isotherms (Langmuir, Freundlich, Dubinin-Radushkevich, Temkin and Halsey), three parameter isotherms (Redlich-Peterson, Sips, Khan, Koble-Corrigan, Hill, Toth, Radke-Prausmitz, Jossens, Langmuir-Freundlich), four parameter isotherms (Weber-van Vliet, Fritz-Schlunder, Baudu) and five parameter isotherm (Fritz-Schlunder). Thermodynamic parameters of the biosorption (ΔG, ΔH and ΔS) were also determined. The present study confirmed that macrofungus P. platypus may be used as a cost effective efficient biosorbent for the removal of Ag(I) ions from aqueous solution.

Nilanjana Mitra

Department of Bio-Medical Sciences

School of Bio Sciences and Technology

Vellore Campus

Das D

Mathew L.

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Journal of Hazardous Materials

Electricals and electronic equipments that have reached its utilization period are disposed by the consumer are considered as e-waste. The categories of e-waste range from household appliances to machines used in offices and consumer goods. The rise in problem is due to scarcity of proper place for disposing the e-wastes. Hence, the wastes are disposed in open landfills by the consumers which lead to direct reaction of the e-waste with the environment. The release of harmful toxins and chemicals by the e-wastes causes hazardous effects on living beings. Several processes are introduced in recycling and recovering the harmful metals present in the electronic equipments. The most important reasons for e-waste recycling are waste removal as well as recovery of valuable materials present in the waste. Developed countries such as USA and UK follow some strict rules and regulations about managing the increasing amount of e-wastes, whereas India still needs to have a rigid law for the e-waste management. Prior recycling and recovering the important metals from electronic wastes, it is crucial to ascertain the amount of the metal present in the e-waste. Plastics followed by metals are the main components found in electronic wastes. Hazardous metals such as copper, lead and cadmium are predominant in almost all kinds of e-wastes. Determination of the components present in the electronic wastes guides for the proper path to be followed for recovering the components from the wastes. The review deals with status of e-waste across the world and methods of recovery and management. © 2016, Islamic Azad University (IAU).

International Journal of Environmental Science and Technology

Efficient management of e-wastes

The current study presents a novel approach for the removal of Ni(II) from aqueous environments using plant gum-based (PG) and clay-based (CL) nanobiocomposite (NBC) composed of ZnO nanoparticles and chitosan. Parameters like pH, contact time, temperature, initial metal concentration and adsorbent dosage were optimized. Under optimized conditions, maximum removal of Ni(II) was noted as 90.1{\%} and 95.5{\%} in the case of PG-NBC and CL-NBC, respectively. Equilibrium studies suggested a homogeneous mode of adsorption. Good linearity was observed for the pseudo-first order kinetic model, suggesting a physical mode of adsorption. Thermodynamic studies showed an endothermic and spontaneous nature of adsorption. The mechanism was further elucidated using SEM, EDX, AFM and FT-IR analysis. Ex-situ studies showed a maximum Ni(II) removal of 87.34{\%} from electroplating wastewater using CL-NBC in column mode. Regeneration studies suggested that CL-NBC could be consistently reused up to 4 cycles.

Korean Journal of Chemical Engineering

Application of novel nanobiocomposites for removal of nickel(II) from aqueous environments: Equilibrium, kinetics, thermodynamics and ex-situ studies

In the present study, response surface methodology (RSM) employing Box-Behnken design was used to optimize the parameters for biosorption of praseodymium(III) onto biowaste materials viz., crab shell (C{\textless}inf{\textgreater}R{\textless}/inf{\textgreater}S) and orange peel (OP). Various process parameters viz., pH (A: 3.0-9.0), biomass dosage (B: 0.05-0.35g/L), initial metal concentration (C: 50-350mg/L), temperature (D: 20-60°C) and contact time (E: 5-60min) were chosen for optimization. A square root transformation was suggested by the Box-Cox plot in the present case. A low p-value of {\textless}0.0001 validated the significance of the model. Maximum Pr(III) uptake of 57.8mg/g for (C{\textless}inf{\textgreater}R{\textless}/inf{\textgreater}S) and 49.9mg/g for OP was noted under optimum conditions. Among the equilibrium isotherms tested, Langmuir was found to be the best fitted model suggesting a homogeneous mode of biosorption for both the biosorbents. Kinetic studies showed better applicability of pseudo-first order model for C{\textless}inf{\textgreater}R{\textless}/inf{\textgreater}S suggesting physisorption and pseudo-second order model for OP confirming chemisorption as phenomena underlying the process. SEM analysis confirmed the homogeneous mode of biosorption. FTIR studies confirmed the involvement of amine, alcohol, ketone and amide groups in the process of Pr(III) biosorption onto C{\textless}inf{\textgreater}R{\textless}/inf{\textgreater}S and OP. Regeneration studies suggested that the biosorbents could be consistently reused upto 7 cycles with a minor metal leaching of 0.97{\%} and 0.89{\%}.

Ecological Engineering

Optimization of parameters for praseodymium(III) biosorption onto biowaste materials using response surface methodology: Equilibrium, kinetic and regeneration studies

The present study investigates the enhanced removal of total dissolved solids (TDS) from tap water in Vellore using bead and membrane form of nanobiocomposite (CNTs, gum Arabic and chitosan), previously cyclodextrinated, sulfonated and aminated. The potential of beads and membranes was individually exploited in terms of pH, dosage, dilutions and time. Among various pretreated materials, the aminated form of both bead and membrane exhibited the maximum TDS removal efficiency followed by the sulfonated and cyclodextrinated form at pH6.0, dosage value 6.0g/L and time 6h under optimum condition. The materials were characterized in terms of their BET surface area (aminated (198cm2/g){\textgreater}sulfonated (145.6cm2/g){\textgreater}cyclodextrinated (102.3cm2/g){\textgreater}control (78.0cm2/g)). Packed bed column studies were conducted at varying dosages of bead, membrane and sophorolipid and flow rates. A 3-level Box-Behnken design was used to validate the model significance. Equilibrium and kinetic studies were conducted to determine the mode of adsorption and rate of the process. To elucidate the mechanism of the process, spectroscopic analysis using SEM-EDX and FT-IR was done. Regeneration cycles were performed which showed that the novel duo could be successfully regenerated up to 10cycles/day with an effective treatment of 8L of tap water.

Desalination

Enhanced TDS removal using cyclodextrinated, sulfonated and aminated forms of bead–membrane duo nanobiocomposite via sophorolipid mediated complexation

Response surface methodology (RSM) employing 5-level Box-Behnken design was used to optimize the biosorption of cerium(III) onto biowaste materials of animal and plant origin viz. prawn carapace (PC) and corn style (CS). Various process parameters viz. pH (A: 3.0-9.0), biomass dosage (B: 0.05-0.35 g/L), initial metal concentration (C: 50-350 mg/L), contact time (D: 2-6 h) and temperature (E: 20-60 °C) were chosen for optimization. A log transformation was suggested by the Box-Cox plot in the present case. A low p-value of {\textless}0.0001 validated the significance of the model. Maximum Ce(III) uptake of 218.3 mg/g for PC and 180.2 mg/g for CS was noted under optimum conditions. Among the equilibrium isotherms, Freundlich model was found to be the best fitted one suggesting a heterogeneous mode of biosorption on PC whereas Langmuir model showed the best fit suggesting homogeneous mode of cerium biosorption on CS. This was further confirmed by scanning electron microscopy (SEM). Kinetic studies showed better applicability of pseudo-first order model suggesting physisorption as phenomena underlying the process. Film-diffusion was suggested by the non-linearity of the Boyd plot. Thermodynamic studies showed that the process was endothermic and spontaneous. FTIR analysis confirmed a major involvement of the participation of amide, amines, ketones and primary alcohol groups during Ce(III) biosorption. EDAX analysis confirmed the major participation of carbon group during Ce(III) biosorption. This was the first report on parameter optimization of Ce(III) biosorption onto biowaste materials using 5-level Box-Behnken experimental design which might be helpful for the recovery of Ce(III) from aqueous environment.

Journal of Rare Earths

Optimization of parameters for cerium(III) biosorption onto biowaste materials of animal and plant origin using 5-level Box-Behnken design: Equilibrium, kinetic, thermodynamic and regeneration studies

Recovery of precious metals like gold, silver, palladium platinum etc. is interesting due to its high market prices along with various industrial applications. Conventional technologies viz. ion exchange, chemical binding, surface precipitation etc. which been have been developed for the recovery of such metals are not economically attractive. Biosorption represents a biotechnological innovation as well as a cost effective excellent tool for recovery of precious metals from aqueous solutions. A variety of biomaterials are known to bind the precious metals including algae, fungi, bacteria actinomycetes, yeast etc. along with some biopolymers and biowaste materials.The metal binding mechanism , as well as the parameters influencing the uptake of precious metals and isotherm modeling are presented. This article provides an overview of past achievements and present scenario of biosorption studies carried out on the use of some promising biosorbents which could serve as an economical means for recovering precious metals. The present review also highlights the use of biosorbents in real situations and hopes to provide insights into this research frontier. {\textcopyright} 2010 Elsevier B.V. All rights reserved.

Hydrometallurgy

Recovery of precious metals through biosorption — A review

Sorption capacity of oyster mushroom (Pleurotus platypus), button mushroom (Agaricus bisporus) and milky mushroom (Calocybe indica) were evaluated on biosorption of heavy metals, viz. cadmium (II) and lead (II) from aqueous solutions. The optimum sorption conditions were studied for each metal separately. The desired pH of the aqueous solution was found to be 6.0 for the removal of cadmium (II) and 5.0 for removal of lead (II) for all the mushrooms. The percent removal of both the metals was found to increase with the increase in biosorbent dosage and contact time. The fitness of the biosorption data for Langmuir and Freundlich adsorption models was investigated. It was found that biosorption of cadmium (II) and lead (II) ions onto the biomass of the three mushrooms were better suitable to Langmuir than Freundlich adsorption model. P. platypus showed the highest metal uptake potential for cadmium (qmax 34.96 mg/g) whereas A. bisporus exhibited maximum potential for lead (qmax 33.78 mg/g). Milky mushroom showed the lowest metal uptake capacity for both the metals. The present data confirms that mushrooms may be used as efficient biosorbent for the removal of cadmium (II) and lead (II) ions from aqueous solution. © 2009 Elsevier B.V. All rights reserved.

Biosorption of cadmium (II) and lead (II) from aqueous solutions using mushrooms: A comparative study

Chemical Engineering Journal

Equilibrium, thermodynamic and kinetic studies on biosorption of Pb(II) and Cd(II) from aqueous solution by macrofungus (Lactarius scrobiculatus) biomass

Journal	Data powered by TypesetJournal of Hazardous Materials
Publisher	Data powered by TypesetElsevier BV
ISSN	0304-3894
Open Access	0