Removal of Cd(II) and Cu(II) from aqueous solution using Bengal gram husk as a biosorbent

Abstract

In the present work, Cicer arietinum husk (Bengal gram husk BGH) has efficiently been utilized for the removal of Cd(II) and Cu(II) from aqueous solutions. Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, X-ray diffraction and proximate analysis were used to analyse the biosorbent. Batch experiments were conducted to analyse as well as to evaluate the sorption capacity of metal ions. Factors affecting metal ions adsorption, such as contact time, pH, concentration ranges and adsorbent doses were studied. Maximum sorption of Cu(II) was found at pH 5, while for Cd(II), it was achieved at pH 7. From FTIR and NMR results, it has been found that in BGH, –OH group was present in abundance, and participated in metal complex formation in the sorption experiments. The biosorption process was fast enough because equilibrium reached at 120 min, following pseudo-second-order kinetics. The biosorption data fitted well in the Langmuir isotherm model, indicating the monolayer sorption. The maximum biosorption capacity of BGH, using Langmuir adsorption plots has been determined as 8.58 and 9.70 mg g−1 for Cd(II) and Cu(II), respectively.