Effect of pH and Contact Time on the Adsorption of Pb(II) by <i>Kapok</i> Wood (<i>Ceiba pentandra</i>) Sawdust Based Biosorbent

Abstract

With rapid industrial development, the water pollution due to industrial wastewater discharge also increases. Wastewater containing heavy metals such as Lead (Pb(II)) has been one of the serious global issues. It is because lead has a high level of toxicity and very harmful to the environment as well as human body even at low level of concentration. One of the emerging methods for removal of Pb(II) from aqueous solution is called biosorption. It is adsorption process using biomass-based adsorbent or can be called biosorbent. One of biomass material that can be used for the biosorbent for removal of Pb(II) is Kapok wood sawdust. In this study, biosorbent based Kapok sawdust has been successfully prepared. The effects of pH and contact time on the adsorption performance of the biosorbent have been studied. The adsorption tests were carried out with variations in pH 4, 5, 6, and 7 and with variations in contact time of 30, 60, and 90 minutes. The amout of Pb(II) adsorbed was analyzed using Atomic Absorption Spectroscopy (AAS). The adsorption test results showed that the equilibrium contact time required for the biosorbent to absorb Pb(II) was 60 minutes, while the pH optimum was achieved at pH = 7. Furthermore, from the adsorption test results, it has also been concluded that the optimum adsorption capacity (qe) 4.83 mg/g and removal percentage (96.6%) was achieved by Adsorbent A (i.e. Kapok sawdust biosorbent activated with 0.2 M HNO3).