No abstract

No abstract

The objective of this study is to prepare and characterize chitosan/zeolite biocomposite beads and utilize them as adsorbent for removal of anionic dye, Acid Black 194 (AB194). Characterization studies of biocomposite beads were carried out by using Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy energy dispersive X-ray spectroscopy (SEM-EDX). The ability of chitosan/zeolite biocomposite beads as an adsorbent for the removal AB194 from an aqueous solution has been investigated under various experimental conditions. Maximum adsorption capacity of biocomposite beads was calculated as 2140 mg/g. The increase in temperature resulted in a higher AB194 loading per unit weight of biocomposite beads. As an additional factor affecting the adsorption behavior of AB194, the effect of ionic strength was investigated, and the adsorption capacity of biocomposite beads significantly decreased. Four isotherm models were employed to elucidate the adsorption process. The most appropriate model for the equilibrium process was the Freundlich. The kinetic studies indicated that the adsorption of AB194 followed the pseudo-second-order kinetics. Thermodynamic calculations showed that the adsorption of reactive dye was a spontaneous and endothermic process. The obtained results indicate that chitosan/zeolite biocomposite beads as an adsorbent are promising for dye removal from wastewater.

No abstract

No abstract

No abstract

Papain, which is an industrially important enzyme, has been immobilized on fibrous polymer-modified composite beads, namely poly(methacrylic acid)-grafted chitosan/clay. Characterization studies have been done using FTIR and SEM analysis. Operating parameters such as pH and initial concentration of papain have been varied to obtain the finest papain immobilized polymer-modified composite beads. The immobilization capacity of composite beads has been determined as 34.47 ± 1.18 (n = 3) mg/g. The proteolytic activity of immobilized papain was operated using bovine serum albumin (BSA) and maximum velocity (V max) and Michaelis-Menten constant (Km) values of the free and immobilized enzymes were determined using Lineweaver-Burk and Eadie-Hofstee equations. Usability of papain immobilized polymer-modified composite beads as adsorbents for the elimination of mercury was investigated. The maximum removal capacity of PIPMC beads has been found to be 4.88 ± 0.21 mg Hg/g when the initial metal concentration and weight of polymer-modified composite beads were 50 mg/L and 0.04 g at pH 7, respectively. Mercury removal performance of the papain immobilized polymer-modified composite beads was investigated in conjunction with Cu (II), Zn (II) and Cd (II) ions. The mercury adsorption capacity of papain immobilized polymer-modified composite beads was a slight reduction from 1.15 to 0.89 mg/g in presence of multiple metal salts.

No abstract