Synthesis and Characterization of Novel β-CD-Xanthate and Its Application in the Treatment of Heavy Metal Containing Wastewater and Lignin Enriched Paper Industry Wastewater

Abstract

Three grades of xanthates of β-cyclodextrin (β-CD) viz. β-CDX1 β-CDX2 and β-CDX3 have been synthesized by the rection of β-CD with CS2 in alkaline medium (NaOH), through xanthation process. The synthesized β-CDXs have been characterized by UV, FTIR, 1HNMR, DSC, ΔpHPZC and SEM analysis. Further, β-CDXs and raw β-CD has been used for the heavy metals removal (Cu2+ and Ni2+) and also lignin removal from lignin enriched paper industry wastewater (LEPIW). The maximum % removal of β-CD, β-CDX1, β-CDX2 and β-CDX3 have been found to be 73.6, 91.9, 93.4 & 95.8% for Cu2+ ion and 65.8, 88.6, 91.3 & 94.1% for Ni2+ ion at optimum adsorbent dosage 2.0 g/L, pH 6.5, initial concentration 1000 mg/L, temperature 45 oC for Cu2+ and 55 oC for Ni2+, and contact time: 80 min for Cu2+ and 100 min for Ni2+ ion respectively. While LEPIW treatment efficacy of 54, 77, 83 and 86% has been noticed (initial COD: 2.0 g/L, pH: 7, optimum temperature: 40°C at 80 min operating time) for β-CD, β-CDX1, β-CDX2 and β-CDX3 respectively. The calculated data fitted well with Langmuir isotherm model confirming the adsorption of Cu2+ & Ni2+ ions onto the β-CDXs adsorbent is monolayer. The rate of adsorption of heavy metals (Cu2+ and Ni2+) on the β-CDXs adsorbent has been controlled by kinetic model of Pseudo second order indicating the chemisorption. The optimal adsorption capacities of β-CD, β-CDX1, β-CDX2 and β-CDX3 has been found to be 357.14, 473.93, 510.20 & 534.75 mg/g for Cu2+ and 294.11, 384.61, 408.16 & 423.72 mg/g and for Ni2+ ions, respectively.