Kinetics and equilibrium studies for the removal of heavy metals in both single and binary systems using hydroxyapatite

Abstract

Removal of heavy metals is very important with respect to environmental considerations. This study investigated the sorption of copper (Cu) and zinc (Zn) in single and binary aqueous systems onto laboratory prepared hydroxyapatite (HA) surfaces. Batch experiments were carried out using synthetic HA at 30°C. Parameters that influence the adsorption such as contact time, adsorbent dosage and pH of solution were investigated. The maximum adsorption was found at contact time of 12 and 9 h, HA dosage of 0.4 and 0.7 g/l and pH of 6 and 8 for Cu and Zn, respectively, in single system. Adsorption kinetics data were analyzed using the pseudofirst-, pseudosecondorder and intraparticle diffusion models. The results indicated that the adsorption kinetic data were best described by pseudosecond-order model. Langmuir and Freundlich isotherm models were applied to analyze adsorption data, and Langmuir isotherm was found to be applicable to this adsorption system, in terms of relatively high regression values. The removal capacity of HA was found to be 125 mg of Cu/g, 30.3 mg of Zn/g in single system and 50 mg of Cu/g, 15.16 mg of Zn/g in binary system. The results indicated that the HA used in this work proved to be effective material for removing Cu and Zn from aqueous solutions.

Synthesis and characterization of hydroxyapatite nanoparticles impregnated on apple pomace to enhanced adsorption of Pb(II), Cd(II), and Ni(II) ions from aqueous solution

“…Nanoparticles (NPs) have high potential for the tertiary wastewater treatment technology because of their small size (1-100 nm), catalytic potential, highly reactive and large surface area, ease of separation, large number of active sites, and regeneration ability (Ali 2012). Hydoxyapatite (Ca 10 (PO 4 ) 6 (OH) 2 ) is an ideal adsorbent because of its high sorption capacity for heavy metals, low water solubility, easy availability, low cost, and applicability under oxidizing and reducing conditions (Meski et al 2010;Ramesh et al 2012). Recently, Tang et al (2013) reported removal of Cr(VI) from aqueous solution using hydroxyapatite nanoparticles (HANPs) of different Ca/P ratios.…”

Removal of heavy metals and bacteria from aqueous solution by novel hydroxyapatite/zeolite nanocomposite, preparation, and characterization

“…Recently, Ramesh et al [16] have used a hydroxyapatite as an adsorbent in the removal of heavy metals in both single and binary systems. Corami et al [17] studied the removal of copper and zinc by hydroxyapatite, while Sairam Sundaram et al [18] have synthesized nanohydroxyapatite and tested it for the removal of fluoride.…”

Risk assessment of heavy metal contamination in sediments of a tropical lake

“…Heavy metal contamination of urban lakes is a serious pollution problem due to their persistent and bioaccumulative nature (Miguel et al 2007;Ramesh et al 2012;Sun et al 2010). Heavy metals like Cr, Ni, Pb, Cd, and As in sediments are known to exhibit extreme toxicity even at trace levels (Rai 2009;Adakole and Abolude 2012).…”