Biosorption of Lead Ions from Aqueous Solution Using Ficus benghalensis L.

Ficus benghalensis L., a plant-based material leaf powder, is used as an adsorbent for the removal of lead ions from aqueous solution using the biosorption technique. The effects of process parameters such as contact time, adsorbent size and dosage, initial lead ion concentration, and pH of the aqueous solution on bio-sorption of lead by Ficus benghalensis L. were studied using batch process. The Langmuir isotherm was more suitable for biosorption followed by Freundlich and Temkin isotherms with a maximum adsorption capacity of 28.63？mg/g of lead ion on the biomass of Ficus benghalensis L. leaves. 1. Introduction The removal of toxic metal ions and the recovery of valuable ions from wastewaters, soils, and waters are important in economic and environmental problems. Heavy metals and other metal ions exist as contaminants in aqueous waste streams of many industries, such as tanneries and mining. Some metals associated with these activities are Pb, Hg, Cr, and Cd. Toxic metals are released into the environment in a number of ways. Coal combustion, sewage wastewaters, automobile emissions, battery industry, mining activities, and the utilization of fossil fuels are just a few examples. Some of these metals accumulate in living organisms and cause various diseases and disorders. Heavy metals such as lead, mercury, arsenic, copper, zinc, and cadmium are highly toxic when adsorbed into the body [1]. They can cause accumulative poisoning, cancer, brain damage, and so forth. Lead is a general metabolic poison and enzyme inhibitor. It can cause mental retardation and semipermanent brain damage in young children [2]. Lead has the ability to replace calcium in the bone to form sites for long-term release, hence, the imminent need to remove these toxic metals from waters and wastewaters. The permissible limit of lead in wastewater as set by the Environment protection Agency is 0.1？mg/L, whereas in drinking water it is 0.05？mg/L [3]. Among the various water-treatment techniques described, adsorption is generally preferred for the removal of heavy metal ions due to its high efficiency, easy handling, availability of different adsorbents, and cost effectiveness [4]. Earlier studies demonstrated that the living systems could often be unreliable because of many associated problems in maintaining active microbial populations under highly variable conditions of wastewaters [5]. Therefore, some types of biomass are often chosen to serve as biosorbents to remove heavy metals [5–8]. Biosorption, a term that describes the removal of heavy metals by passive binding to