There have been a number of studies that have examined metal precipitation reactions on an array of natural soil materials. While many of these investigations have focused on model single-component systems, recent research has appeared on metal precipitation on soils and clay fractions of soils. However, few studies have explored mixed model component systems, which may lead to a better underst...

Hexavalent chromium, Cr(VI), can be immobilized under neutral to alkaline conditions by reduction to Cr(III); similarly, the mobility of naturally occurring Cr in soils and sediments can be limited by its occurrence in the +III oxidation state. Conversely, the oxidation of Cr(IIi) to Cr(VI) increases both its toxicity and often its mobility. Dissolution of Cr-(OH)3(s) in 0.01 M NaNO3 suspension...

The aim of this study is to investigate the nitrate adsorption on granular ferric hydroxide (GFH). The effect of factors such as initial concentration of nitrate, pH, contact time, and adsorbent mass were determined. The study was done in laboratory–scale in which synthetic nitrate solutions in a batch reactor were placed in contact with the adsorbent to model adsorption kinetics. It was found ...

Arsenic (As) carcinogenicity to humans and other living organisms has promulgated extensive research on As treatment technologies with varying levels of success; generally, the most efficient methods come with a significantly higher cost burden and they usually perform better in removing As(V) than As(III) from solution. In the reported study, a novel sorbent, a waste by-product of the drinking...

Abstract The potential for the photocatalytic degradation of lindane, used as agricultural insecticide and pharmaceutical product, is investigated. Two types photocatalysts, immobilized on 5 mm sodalime beads are synthesised using an easy economical process: (1) Zinc Oxide (ZnO) nanoparticles (2) Iron oxide-doped (Fe-ZnO). Tests lindane under continuous flow conditions conducted a stainless ste...

the aim of this study is to investigate the nitrate adsorption on granular ferric hydroxide (gfh). the effect of factors such as initial concentration of nitrate, ph, contact time, and adsorbent mass were determined. the study was done in laboratory–scale in which synthetic nitrate solutions in a batch reactor were placed in contact with the adsorbent to model adsorption kinetics. it was found ...

Bioavailability of pesticides sorbed to soils is an important determinant of their environmental fate and impact. Mineralization of sorbed atrazine was studied in soil and clay slurries, and a desorption-biodegradation-mineralization (DBM) model was developed to quantitatively evaluate the bioavailability of sorbed atrazine. Three atrazine-degrading bacteria that utilized atrazine as a sole N s...

Iron (III) oxides are ubiquitous in near-surface soils and sediments and interact strongly with dissolved phosphates via sorption, co-precipitation, mineral transformation and redox-cycling reactions. Iron oxide phases are thus, an important reservoir for dissolved phosphate, and phosphate bound to iron oxides may reflect dissolved phosphate sources as well as carry a history of the biogeochemi...

A signi®cant source of uncertainty in multicomponent transport models is due to reaction parameter estimation error. In this paper, two codes are developed to compute reaction parameter sensitivity coecients, which provide a quantitative measure of the impact of this uncertainty. One of the codes solves the full coupled system of sensitivity equations, while the other applies the operator spli...