Kinetic and thermodynamic investigations of copper (II) biosorption by green algae Chara vulgaris obtained from the waters of Dal Lake in Srinagar (India)

Abstract

Intake of copper (II) heavy metal ions beyond certain permissible limit raises the risk of cancer, liver damage, stomach discomfort and kidney failure. In present study dead green algae Chara vulgaris was used as a sorbent for the elimination of copper (II) from eutrophicated water of Dal Lake in Srinagar India. The roles of pH, equilibrium time and initial copper (II) concentration were evaluated in the said biosorption process. Various analyses, including FTIR, FE-SEM/EDX, HR TEM, XRD, and BET tests, were conducted to understand the copper (II) biosorption mechanism. In present investigation the adsorption of copper (II) ions (from 100 ppm concentration of copper (II) solution) was maximum (about 70 %± 1.5) under conditions; pH 5, equilibrium time 60 min, adsorbent dosage 0.5 g in 50 mL of copper (II) solution, and temperature of 20 °C. The adsorption was better fitted by the pseudo-second-order rate model. The experimental findings indicated the Langmuir model was better suited to the given adsorption processes. The said model demonstrated the involvement of both physical and chemical factors underlying the mechanism of process. The values of thermodynamic parameters ΔG0, ΔH0, and ΔS0under given experimental conditions indicated the process to be spontaneous. Moreover, this work presents a fresh approach for environmentally friendly and affordable extraction of copper (II) from wastewater, utilizing algae Chara vulgaris as a biosorbent. The unique biochemical composition of Chara vulgaris demonstrates a remarkable affinity for copper (II) ions, offering a sustainable approach to mitigate copper pollution.