Adsorption of Fe , Pb , Zn and Cr ions from aqueous solutions using natural, ammonium oxalate and sodium hydroxide modified Kaolinite clay

001 Ife Journal of Science vol. 22, no. 3 (2020) INTRODUCTION Effluents discharge from industries is a major source of environmental pollution globally. Heavy metals are one of the dominant contaminants in industrial effluents and discharging heavy-metal laden contaminated wastewater into water bodies at elevated concentrations is considered lethal to living organisms. Excessive accumulation of metal ions in living tissue impedes the biological functions of vital organs resulting into health problems (Chandra and Mandal, 2000; Jiang et al., 2010). Several treatment methods have been devised for removal of heavy metals from wastewater. Adsorption technique is considered one of the effective low-cost methods for removal of heavy metals. Adsorption of heavy metals from aqueous solutions has been studied using different adsorbents including clay (Sari et al., 2007; Adebowale et al., 2008; Dawodu and Akpomie, 2014). The use of kaolinite clay for adsorption is worthwhile because of its abundance in deposit especially in Nigeria (Olusola et al., 2011; Fakoluji et al., 2012). Kaolinite clay is a phyllosilicate clay mineral of interlayer structure type 1:1 with ideal structural formula of Al Si O (OH) (Barth, 1994; 2 2 5 4 Bergaya et al., 2006; Uddin, 2017). Several researchers have investigated the adsorption of heavy metal ions in aqueous solution on kaolinite 2+ clay. The data obtained from adsorption of Pb , 2+ 3+ 2+ 2+ Cu , Fe , Mn and Zn ions on kaolinite showed that there was favourable adsorption of the metal ions (Kamel et al., 2004). Investigation of 2+ 2+ 2+ 2+ adsorption of Pb , Cu , Cd , and Zn ions on 2+ different clays have shown that Pb ion, has greater affinity for the clays than the other metal ions (Olaofe et al., 2015). Nigerian kaolinite clay https://dx.doi.org/10.4314/ijs.v22i3.1