Rice husk as a potential source for the sol-gel synthesis of diphenylcarbazide immobilized silica adsorbent for the adsorption of lead

Abstract

Heavy metals can cause long-term environmental hazards due to its feature of toxicity, bioaccumulation, and non-degradable. Heavy metals can be obtained from volcanic dust and human activities such as domestic waste and industrial waste. One of the widespread heavy metals such as lead (Pb) can be detrimental to human health. The removal of Pb in the environment has been carried out through several methods. One of the most efficient methods denotes by using adsorption. Commonly, adsorbents are used to remove Pb including activated carbon, zeolite, and silica. As one of the adsorbent materials, silica is widely used in purification and separation due to its adsorption properties, high surface area, and porosity. Rice husk has the potential to be used as a source of raw material for making silica. Silica from rice husk can be collected using the sol-gel method as a simple way. This review recommends the modification process through the addition of diphenylcarbazide immobilization onto the silica. This modification may increase the adsorption capacity of silica towards Pb. This review finding indicates that modified silica with diphenylcarbazide immobilization could potentially be applied as an adsorbent to remove Pb, implicating a potentially novel application in the treatment of environmental pollution.