Bioremediation of Ni2+, Cd2+ and Pb2+ from aqueous solution using chemically modified Newbouldia Leavis seed pod. Kinetics and Intraparticle Diffusivities.

This study investigates the biosorption of Ni2+, Cd2+ and Pb2+ from aqueous solution by modified Newbouldia Leavis seed pod. The modification was done by acid treating air-dried activated Newbouldia Leavis seed pod by dissolving it in excess 1.0 M Mercapto acetic acid (HSCH2COOH) solution, stirred for 30 minutes and left to stand for 24 hours at 30 oC, filtered off using WhatmanNo. 41 filter paper and were air dried. The effects of solution pH and contact time were evaluated. The results showed that maximum Cd2+ and Ni2+ adsorption of 7.9872 mg/g and 7.9809 mg/g respectively occurred at pH of 6.0 while that of Pb2+ was 8.0000 mg/g, at a pH of 4.0. The optimum time for maximum adsorption of the three heavy metal ions were 110 min. The kinetic data revealed that the sorption process could best be described by the pseudo – second order kinetic model. The R2 values for the pseudo – second order kinetic plots were unity and were higher than first order reversible model and pseudo – first order plots. Moreover, the values of qcal and qexp obtained for pseudo – second order plots were very close indicating that the biosorption process followed the pseudo-second order kinetics. However, the transport mechanism for the process involved both intra-particle and liquid film diffusion.

Kinetic Investigations on Microwave-Assisted Statistical Terpolymerizations of 2-Oxazoline Monomers

The microwave-assisted statistical terpolymerization of 2-oxazolines via a living cationic ring-opening polymerization mechanism is discussed. Kinetic investigations on the terpolymerizations of combinations of 2-methyl-2-oxazoline, 2-ethyl-2-oxazoline, 2-nonyl-2-oxazoline, and 2-phenyl-2-oxazoline were performed by heating separate polymerization mixtures for different predefined times. The resulting polymer solutions were analyzed by gas chromatography and size exclusion chromatography, demonstrating the living character of the statistical terpolymerizations. In addition, the monomer distribution throughout the polymer chains is discussed based on the linear first order kinetic plots of the separate monomers in the terpolymerizations. The observed differences in monomer distribution are expected to influence the polymer properties, which will be the focus of future investigations.