Utilization of the agricultural waste (Cicer arientinum Linn fruit shell biomass) as biosorbent for decolorization of Congo red

Abstract

Investigations have been carried out to study the use of Bengal gram fruit shell (SP) as a low-cost, eco-friendly biosorbent for the removal of Congo red (CR) from aqueous solution. Fourier transform infrared spectrometer and SEM were used to carry out characteristic studies on the material prepared. The effects of solution pH, biosorbent dosage, dye concentration, temperature, and contact time on the biosorption of CR onto the SP were investigated. The experimental results showed that maximum pH for efficient CR biosorption was about 8.0. Langmuir and Freundlich isotherm models were used for analyzing the equilibrium data. The maximum monolayer biosorption capacity was found as 22.22 mg g⁻¹ at 35°C. Kinetic studies indicated that the pseudo-second-order model fitted the experimental data well. Thermodynamic parameters demonstrated that the biosorption process was spontaneous and endothermic. The results revealed that the SP could be used as a low-cost and eco-friendly alternative biosorbent for the CR removal from wastewater.

Keywords:

• Bengal gram fruit shell (SP)
• Agricultural by-product
• Congo red
• Thermodynamic parameters
• Kinetics
• Adsorption models
• Wastewater treatment

Acknowledgments

The main author L. Sivarama Krishna would like to acknowledge Sri Venkateswara University, Tirupati. Special acknowledgment to Universiti Kebangsaan Malaysia for financial support to conduct a postdoctoral research.