Removal of Copper and Dyes from Water Solution Using Ethylenediaminetetraacetic Dianhydride (EDTAD) Modified Cellulose

Abstract

Environmental pollution, particularly from heavy metals and dyes in wastewater, is a serious problem in many parts of the world. EDTAD-modified cellulose extracted from Pennisetum purpureum was studied as a low-cost adsorbent for removing heavy metals and dyes from synthetic water. A Fourier transform IR spectrophotometer, Shimadzu 8400 CE, was used to analyze functional groups of cellulose and EDTAD modified cellulose. The characteristic peaks at 1260 cm-1, 1634 cm-1, 1058 cm-1, and 1740 cm-1 indicated the formation of ester bond linkages associated with the introduction of C-O bond, thus successful modification of cellulose. A Shimadzu UV-VIS 1800 series determined the extent of dye concentration. Optimum adsorption was determined by varying the pH level, dosage, contact time, and the initial concentration of the dyes. Low pH levels prompted low % removal as compared to higher pH values in both dyes. Freundlich and Langmuir's isotherms were used to investigate the rate and mechanism of adsorption. Methylene blue and neutral red dyes conformed to the Freundlich isotherm with high R2 values of 0.990 and 0.993, respectively, while Langmuir had values of 0.476 and 0.813, indicating the surface of the EDTAD-modified cellulose was heterogeneous. Adsorption capacity was 200 mg/g for Methylene Blue and 149.25 mg/g for Neutral Red dye. An Atomic Absorption Spectrometer was used for copper metal determination. The highest percentage removal for Cu (II) ions was at pH 6, a sorbent mass of 0.2 grams, and an optimum contact time of 120 minutes. Adsorption isotherm data fitted well in Langmuir isotherm where R2 was found to be 0.9989 indicating that monolayer adsorption was prevalent. Kinetic data fitted well in both Pseudo first order and second order kinetic indicating that both physical and chemical adsorption was prevalent. EDTAD-modified cellulose was efficiently used in the removal of dyes and Cu (II) ions.