Unmodified Biomass Research Articles

Adsorption study of copper (II) by chemically modified orange peel

An adsorbent, the chemically modified orange peel, was prepared from hydrolysis of the grafted copolymer, which was synthesized by interaction of methyl acrylate with cross-linking orange peel. The presence of poly (acrylic acid) on the biomass surface was verified by infrared spectroscopy (IR), scanning electron microscopy (SEM) and thermogravimetry (TG). Total negative charge in the biomass surface and the zeta potentials were determined. The modified biomass was found to present high adsorption capacity and fast adsorption rate for Cu (II). From Langmuir isotherm, the adsorption capacity for Cu (II) was 289.0 mg g −1, which is about 6.5 times higher than that of the unmodified biomass. The kinetics for Cu (II) adsorption followed the pseudo-second-order kinetics. The adsorbent was used to remove Cu (II) from electroplating wastewater and was suitable for repeated use for more than four cycles.

Biosorption of cadmium and nickel by functionalized husk of Lathyrus sativus

The husk of Lathyrus sativus (HLS) has been functionalized by introducing thio groups with the help of carbon disulphide treatment in alkaline environment. Elemental analysis indicates that sulphur content of the functionalized biomass increases to 3.7% from 0.36% of the pristine biomass suggesting the incorporation of thio group on HLS. A conspicuous change in the surface morphology of the biomass due to functionalization is depicted by SEM images. EDX data support the introduction of sulphur group on the HLS. The involvement of the hydroxyl groups mainly in the functionalization process is demonstrated by Fourier transform infrared (FTIR) spectroscopic study. The adsorption capacity of the functionalized biomass with respect to cadmium and nickel is observed to increase by about 50% compared to that of pristine one. Similar to the case of unmodified HLS the adsorption process involving the functionalized one obeys Langmuir isotherm model and attains equilibrium in 10 min compared with 60 min in the case of unmodified biomass.

Enhanced and selective adsorption of Pb 2+ and Cu 2+ by EDTAD-modified biomass of baker’s yeast

Enhanced and selective removal of Pb 2+ and Cu 2+ in the presence of high concentration of K +, Na +, Ca 2+ and Mg 2+ were achieved by adsorption on biomass of baker’s yeast modified with ethylenediaminetetraacetic dianhydride (EDTAD). The modified biomass was found to have high adsorption capacities and fast rates for Pb 2+ and Cu 2+, and it also displayed consistently high levels of metal uptake over the pH range from 2.7 to 6.0. From Langmuir isotherm, the adsorption capacities for Pb 2+ and Cu 2+ were found to be 192.3 and 65.0 mg g −1, respectively, which are about 10 and 14 times higher than that of the unmodified biomass. Competitive biosorption experiments showed that the co-ions of K +, Na +, Ca 2+ and Mg 2+ had little effects on the uptake of Pb 2+ and Cu 2+ even at the concentration of 1.0 mol L −1. The adsorbed Pb 2+ and Cu 2+ on the modified biomass could be effectively desorbed in an EDTA solution, and the regenerated biomass could be reused repeatedly with little loss of the adsorption capacity.

Sorption kinetics of Pb2+ and Cu2+ ions from aqueous solution by Nipah palm (Nypa fruticans Wurmb) shoot biomass

The sorption kinetics of Pb2+ and Cu2+ ions in aqueous solution by unmodified and mercaptoacetic acid modified biomass of Nypa fruticans shoot has been investigated. The equilibrium sorption capacity of Pb2+ and Cu2+ was determined from the Langmuir equation and found to be 15.59 mg/g and 21.85 mg/g for unmodified biomass and 52.86 mg/g and 66.71 mg/g for modified biomass at 30°C. The time dependent studies showed relatively rapid sorption of 5 - 10 min to reach equilibrium for both metal ions. A batch sorption model, based on the assumption of the pseudo-second-order mechanism, was applied to predict the rate constants (g mg-1 min-1), which were found to be 3.59 x 10-4 (Pb2+) and 1.85 x 10-4 (Cu2+) and 2.82 x 10-2 (Pb2+) and 3.67 x 10-2 (Cu2+) on unmodified and mercaptoacetic acid modified biomass respectively. The activation energy of the sorption of Pb2+ and Cu2+ on Nypah palm reveals an endothermic process.

Sorption kinetics of Pb2+ and Cu2+ ions from aqueous solution by Nipah palm (Nypa fruticans Wurmb) shoot biomass

The sorption kinetics of Pb 2+ and Cu 2+ ions in aqueous solution by unmodified and mercaptoacetic acid modified biomass of Nypa fruticans shoot has been investigated. The equilibrium sorption capacity of Pb 2+ and Cu 2+ was determined from the Langmuir equation and found to be 15.59 mg/g and 21.85 mg/g for unmodified biomass and 52.86 mg/g and 66.71 mg/g for modified biomass at 30oC. The time dependent studies showed relatively rapid sorption of 5 - 10 min to reach equilibrium for both metal ions. A batch sorption model, based on the assumption of the pseudo-second-order mechanism, was applied to predict the rate constants (g mg -1 min -1 ), which were found to be 3.59 x 10 -4 (Pb 2+ ) and 1.85 x 10 -4 (Cu 2+ ) and 2.82 x 10 -2 (Pb 2+ ) and 3.67 x 10 -2 (Cu 2+ ) on unmodified and mercaptoacetic acid modified biomass respectively. The activation energy of the sorption of Pb 2+ and Cu 2+ on Nypah palm reveals an endothermic process.

A new approach to chemical modification protocols of Aspergillus niger and sorption of lead ion by fungal species

Biomasses of five fungi species ( Aspergillus niger , Penicillium austurianum, Saccharomyces cerevisiae, Mucor arcindloides and Trichoderma reesi were evaluated for their uptake of lead ion from aqueous solution using batch systems. Both dead and live fungal biomasses were comparatively studied for their adsorption efficiencies. The effect of pH as one of the primary factors that influences sorption efficiency of metal ions in solution was also studied. Modification of the fungal biomass with the least sorption capacity was carried out using a four-step procedure. Three different modifying agents under the optimised experimental conditions were used. The percentage uptake of lead ion by fungi species ranged from: Aspergillus niger : 6.71-64.95% and 66.91-95.27%; Penicillium austurianum : 44.47-98.85% and 75.57-94.21%; Saccharomyces cerevisiae : 52.61-88.68% and 61.20-89.95%; Mucor arcindloides : 83.78-93.13% and 62.91-97.65% and Trichoderma reesi : 52.52-80.70% and 35.31-88.13% for dead and live biomass respectively. The influence of pH on metal uptake was evaluated at pH of 2, 4, 6 and 7. A regular pattern of sorption efficiency among the dead fungi species with respect to pH was observed and the % adsorption decreased in the order pH 7 > 2 > 6 > 4 with the exception of Mucor (pH 7 > 2 > 4 > 6). Modified biomass of Aspergillus niger with oxalic acid, malic acid and ethylenediamine tetraacetic acid (EDTA) recorded 92.84%, 48.11% and 39.83% uptake of Pb respectively which correspond to 69.65%, 41.23% and 29.25% increase when compared to 28.18% of the unmodified biomass. These quantitative adsorptions demonstrate the potential application of modified biomass for the removal of Pb ion from aqueous solution.

A new approach to chemical modification protocols of Aspergillus niger and sorption of lead ion by fungal species

Biomasses of five fungi species ( Aspergillus niger , Penicillium austurianum, Saccharomyces cerevisiae, Mucor arcindloides and Trichoderma reesi were evaluated for their uptake of lead ion from aqueous solution using batch systems. Both dead and live fungal biomasses were comparatively studied for their adsorption efficiencies. The effect of pH as one of the primary factors that influences sorption efficiency of metal ions in solution was also studied. Modification of the fungal biomass with the least sorption capacity was carried out using a four-step procedure. Three different modifying agents under the optimised experimental conditions were used. The percentage uptake of lead ion by fungi species ranged from: Aspergillus niger : 6.71-64.95% and 66.91-95.27%; Penicillium austurianum : 44.47-98.85% and 75.57-94.21%; Saccharomyces cerevisiae : 52.61-88.68% and 61.20-89.95%; Mucor arcindloides : 83.78-93.13% and 62.91-97.65% and Trichoderma reesi : 52.52-80.70% and 35.31-88.13% for dead and live biomass respectively. The influence of pH on metal uptake was evaluated at pH of 2, 4, 6 and 7. A regular pattern of sorption efficiency among the dead fungi species with respect to pH was observed and the % adsorption decreased in the order pH 7 > 2 > 6 > 4 with the exception of Mucor (pH 7 > 2 > 4 > 6). Modified biomass of Aspergillus niger with oxalic acid, malic acid and ethylenediamine tetraacetic acid (EDTA) recorded 92.84%, 48.11% and 39.83% uptake of Pb respectively which correspond to 69.65%, 41.23% and 29.25% increase when compared to 28.18% of the unmodified biomass. These quantitative adsorptions demonstrate the potential application of modified biomass for the removal of Pb ion from aqueous solution.

Heavy metal binding by inactivated tissues of Solanum elaeagnifolium: chemical and subsequent XAS studies

Contamination caused by heavy metals as well as their toxic effects on the environment and mankind is well known. However, it has been observed that some native plants have survived within areas polluted with heavy metals. This has been the case with the woody subshrub Solanum elaeagnifolium. It is possible to take advantage of this singular feature by using its inactivated tissues as a biofiltration system. In this work we characterized the mechanism of the binding between the biomass tissues with heavy metals by using chemical modification techniques. These techniques included chemical esterification and hydrolyzation of carboxylic groups and methyl esters, respectively. These studies have shown an overall decrease in metal binding for the esterified biomass, and an overall increase in metal binding for the hydrolyzed biomass as compared with the unmodified biomass. These experiments were performed with Cu(II), Pb(II), Cr(III), Zn(II) and Ni(II). In addition, experiments conducted with modified biomass at different pH conditions were done in order to corroborate the biomass modification results. Also, we used X-ray absorption spectroscopy techniques (XANES and EXAFS) to elucidate the mechanism(s) of metal ion binding.