Removal of Cadmium from Aqueous Solutions Using Excised Leaves of Quetta Pine (pinus Halepensis Mill.)

Removal of cadmium from aqueous solution was studied by using Quetta pine (Pinus halepensis Mill.) leaves. Batch adsorption experiments were performed as a function of appropriate equilibrium time, pH, concentration of adsorbate and amount of adsorbent. The optimum pH required for maximum adsorption was found to be 7.0 and the maximum contact time for the equilibrium was 30 minutes at adsorbent dose of 10 g. The maximum adsorption efficiency of cadmium removal was 98.50%. The results were better fitted by Langmuir than Freundlich isotherm. The separation factor of equilibrium 0.12 and 0.67 showed that Quetta pine leaves are good adsorbent of cadmium from aqueous solution. Introduction Due to urbanization and industrialization, the disproportionate release of heavy metals in to the environment has created a serious threat to the biological life worldwide. The heavy metals cannot be degraded to harmless end products like organic pollutants which are susceptible to biological degradation (Gupta et al. 2001). The presence of heavy metals in the environment is of a great concern due to their toxicity to many life forms. Heavy metals are present in aqueous wastes of many industries like metal plating, mining operations, tanneries, smelting, alloy and storage batteries (Kadrivelu et al. 2001). Among heavy metals ion, ions of Cd, Cr, Zn, Hg, Pb gain importance due to their high toxic nature even at very low concentrations. In recent years the development of general environment awareness to common population, the contamination of water is now not the concern of only scientific community. This makes it necessary to develop methods that allow one to detect, quantify and remove these metals from the effluent waters (Khalfaour et al. 1990). Various methods are available to isolate and remove heavy metals from the environment include precipitation, ion exchange, adsorption etc. but the selection of method is based on the concentration of metals and cost of treatment (Cheung et al. 2001, Ajmal et al. 2003). Adsorption is one of the easiest, safe and cost effective methods, being widely used in effluent water treatment processes (Devrim and Hayri 1992). Adsorbent like charcoal, clay, fuller’s earth, saw dust are commonly used adsorbents (Mahvi et al. 2004, Baily et al. 1999). In present study, the possibility of utilization of excised leaves of Quetta pine as an adsorbent for removal of cadmium from aqueous solution is explored. Materials and Methods Quetta pine (Pinus halepensis Mill.) leaves were obtained from the trees grown at PCSIR laboratories, Quetta campus. The adsorbent (Quetta pine leaves) was prepared as by Xio and Ju-Chang (2009). *Author for correspondence: . Department of Botany, University of Balochistan, Quetta, Pakistan. Department of Zoology, University of Balochistan, Quetta, Pakistan.