Sorption isotherms and kinetics of chromium uptake from wastewater using natural sorbent material

Abstract

Chromium (VI) which exists in many industrial wastewater is considered highly toxic. The aim of the present investigation was to study the reduction of chromium (VI) to chromium (III) and then removing it with the help of weathered basalt andesite products. Reduction of the chromium (VI) to chromium (III) by hydrazinium sulfate was investigated. The influence of hydronium ion concentration, contact time, hydrazinium sulphate dosage and temperature has been tested in batch runs. The process was found to be acid, temperature and concentration dependent. The suitability of weathered basalt andesite products as a potential sorbent was assessed for the removal of chromium (III) following batch mode of operation. The effect of various parameters such as hydronium ion concentration, shaking time, sorbent dose, initial metal ion concentration and temperature on the removal of chromium (III) from aqueous solution was studied. Thermodynamic parameters (∆H°, ∆S° and ∆G°) for the sorption process were evaluated. Analysis of sorption obtained results showed that the sorption pattern followed the Freundlich, Langmuir and Dubinin-KaganerRadushkevich isotherms. The process follows pseudo second order rate and surface diffusion is identified as the predominating mechanism. The sorption process was shown to be reversible by the recovery of sorbed chromium (III) upon extraction with 0.5 M nitric acid. The sorbent, before and after sorption, was characterized by fourier transform infrared spectrometer, X-ray diffraction, scanning electron microscope, transmision electron microscope and thermogravimetric analyse methodes. An increase in crystallanity after sorption of chromium was observed. An industrial effluent was successfully treated with the same sorbent with convincing results.

Earthworm-assisted bioremediation of petroleum hydrocarbon contaminated soil from mechanic workshop

“…Tel: +2348035600744. gens), lead, arsenic, zinc and cadmium, which can seep into the water table and contaminate ground water (Igwe et al, 2008;Shah et al, 2009). It consequently results in serious health hazard such as anemia and tremors, which can cause death.…”

Heavy metals accumulation in plants growing in ex tin mining catchment

“…Some plant species can grow in these severe conditions. Excessive concentration of heavy metals in plants can cause oxidative stress and stomatal resistance (Fayiga et al, 2004;Shah et al, 2009). It can also affect photosynthesis and chlorophyll florescence processes (Monni et al, 2001).…”

Urbanization impact on metals mobility in riverine suspended sediment: Role of metal oxides

“…Impacts of anthropogenic activities on metal contamination in a watershed are far from being insignificant (Horowitz et al, 1999;Davis et al, 2001;Taylor and Owens, 2009;Igbinosa and Okoh, 2009). They are known to generate a considerable amount of metal to the environment through various pathways including atmospheric particles (Azimi et al, 2005;Zhu et al, 2009), urban runoff (Gromaire-Mertz et al, 1999;Igwe et al, 2008), industrial and wastewater effluents (Buzier et al, 2006;Nwuche, 2008;Shah et al, 2009). Urbanization impacts on metal contamination concern watersheds inhabiting more than 50 % of the world population (Meybeck, 2003).…”