A review on biosorptive removal of dyes and heavy metals from wastewater using watermelon rind as biosorbent

Abstract

Sustainable wastewater treatment is one of the foremost challenges of twenty first century. With the ever increasing levels of industrial toxic sludge disposal to water bodies, finding environment friendly and affordable treatment options will remain a priority, especially for developing countries. Adsorption is one of the most researched and used wastewater treatment methods for removing dyes and heavy metals. Adsorption using living and non-living biomass, termed as biosorption has gained attention in the last two decades due to some promising results. Agricultural waste materials e.g. fruit wastes has been widely used for dye and heavy metal sequestration from wastewater. Various researchers have analyzed the potential of watermelon rind (WMR) as a biosorbent for wastewater treatment and have found encouraging results. Functional groups such as carboxyl and hydroxyl are primarily responsible for sorption of dyes and metals into watermelon rind. The most important parameters affecting the biosorption of contaminants using watermelon rind were found to be pH and co-solute concentration. Kinetic and isotherm studies performed by numerous authors revealed that pseudo second order kinetic model and Langmuir isotherm model were best suited for describing WMR based biosorption of dyes and heavy metals. The feasibility of WMR as a reusable biosorbent has been further proved by the results of desorption studies performed by several researchers. This paper reviews the various important aspects of utilization of watermelon rind as a biosorbent for removing dyes and heavy metals from contaminated water. The effects of several factors such as pH, initial solute concentration, biosorbent dose, co-solute concentration, activation etc. has been reviewed in this paper.

Keywords

• Wastewater treatment
• Biosorbent
• Watermelon rind
• Dyes
• Heavy metals