CHARACTERIZATION OF HEAVY METAL REMOVAL FROM AQUEOUS SOLUTIONS USING NATURAL FIBER IMPREGNATED WITH METALLIC NANOPARTICLES

摘要

Heavy metals are found in varying concentrations in anthropogenically influenced water sources including waste water discharge from mining operations. The heavy metals need to be removed to meet applicable discharge standards and to eliminate potential health effects. There has been substantial research recently in the field of water treatment technologies to produce low-cost materials that have metal-binding capabilities. The goal of this research is to characterize the toxic metal removal capabilities of a novel, low cost water treatment system.This research uses a natural fiber substrate and incorporates specific nanometallic particles to remove toxic heavy metals from water. Natural fiber (NF) and metallic nanoparticle treated fiber (MNP) were subjected to various concentrations of copper, cadmium, nickel, and zinc. The research included kinetic experiments, adsorption isotherm experiments, and flow through column tests.The results indicated that the fibers performed consistently well in removing copper with all metal removal efficiencies between 41%-58% for NF and 56%-77% for MNP in a mixed metal solution where the metals were each present at 1 mg/L. NF and MNP were both found to follow a pseudo first order kinetic adsorption model and had processes that followed Langmuir and Freundlich isotherms. MNP was able to reduce initial metals concentrations of 1 mg/L by 50% in 10-30 minutes whereas NF took 20-50 minutes. Metal adsorption is mass transfer limited and concentration gradients appear to be the driving force behind the adsorption rate.Flow through column tests using synthetic mixtures of the four metals of concern, showed consistently high reduction in copper ranging from 78%-90%. Zinc consistently had the lowest removal efficiency and ranged between 24%-62%. A fortified mine tailing water solution with metals was also tested and removal efficiencies reached as high as 87%. MNP performed better overall in experimentation than NF. The fiber filter system is proven to be effective for treating heavy metal contamination from industrial waste streams.