Assessment of the performance of SDS-impregnated brewery waste as suitable adsorbent for the removal of Pb and Cd from water

Abstract

— Due to increasing populations and an ever-changing climate, limited water resources are South Africa’s burden. Clean water is important for all living organisms’ health and environmental sustainability. To achieve efficient and cost-effective ways of removing heavy metals from water, the development of different water treatment technologies are important. This study evaluates the performance of organic waste in the form of brewery waste as suitable adsorbent for removing Pb and Cd from water. Raw brewery waste was treated with sodium dodecyl sulphate (SDS) to investigate whether pre-treatment of raw organic waste can possibly enhance the removal rate of metals. Characterization of the adsorbents was done by FTIR analyses. Pseudo-first-order and pseudo-second-order kinetic models were utilized as well as the Langmuir and Freundlich isotherm models to determine the adsorption rate and affinity of the adsorbents. Other factors influencing the adsorption process that was investigated include the effects of adsorbent dosage, contact time, initial metal ions concentration and temperature. The untreated brewery waste removed 68.17% Pb(II) and 56.28% Cd(II) which increased to 95.30% Pb(II) and 83.29% Cd(II) when treated with SDS. Treatment of brewery waste can be used to enhance the adsorption capacity. Thermodynamic parameter evaluation indicated that the adsorption process was endothermic in nature and thermodynamically favourable in the case of treated brewery waste. Treated brewery waste can therefore be used for efficient Pb and Cd removal from water