Biosorption of heavy metals using rice milling by-products. Characterisation and application for removal of metals from aqueous effluents

• Published in: Chemosphere (Oxford) Vol. 54; no. 7; pp. 987 - 995
• Main Authors: Teixeira Tarley, César Ricardo, Zezzi Arruda, Marco Aurélio
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-02-2004; Elsevier
• Subjects: Adsorption; Agriculture, rearing and food industries wastes; Applied sciences; Effluent treatment; Exact sciences and technology; General purification processes; Heavy metals; Hydrogen-Ion Concentration; Metals, Heavy - chemistry; Microscopy, Electron, Scanning; Oryza - chemistry; Oryza - ultrastructure; Oryza sativa; Particle Size; Pollution; Rice husks; Spectrometry, X-Ray Emission; Spectrum Analysis; Thermogravimetry; Wastes; Wastewaters; Water Purification - methods; Water treatment and pollution; X-Ray Diffraction; Effluent treatment; Rice husks; Heavy metals; Liquid solid adsorption; Thermogravimetry; Bioadsorbents; Rice by product; Vegetal waste; Heavy metal; Characterization; Biosorption; Upgrading; Waste reuse; Chemical composition; Physicochemical purification; Agricultural waste; Waste water purification; Performance
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2003.09.001

The morphological characteristics as well as chemical composition of rice husks were evaluated by different techniques such as spectroscopy and thermogravimetry. The material, which is considered a by-product obtained from rice milling, was then investigated as a potential decontaminant of toxic heavy metals present in laboratory effluents. Studies using glass columns were carried out at room temperature employing 100 ml of synthetic solutions containing Cd(II) and Pb(II) at 100 mg
l
−1 in order to study the effects of pH, flow rate and particle size on Cd(II) and Pb(II) adsorption. After establishing the optimised conditions, the potentiality of rice husks for removing Cd(II) and Pb(II) ions from 100 ml of laboratory effluent, presenting concentrations before treatment of 22 and 12 mg
l
−1, respectively, was evaluated. The ability to take up other metals species, such as Al(III), Cu(II) and Zn(II), present in this effluent was also studied. According to the data obtained, under the optimised conditions (pH=4.0, flow rate of 8.0 ml
min
−1 and ⩽355 μm rice husk particle size), 30 g of husks were necessary to attain the permissible limits for effluent release, as recommend by the EPA, for those species evolved in this work (Al, Cd, Cu, Pb and Zn).