Synthesis, characterization and adsorption of Malachite green dye using novel materiel produced from opuntia ficus indica

Abstract

Opuntia ficus-indica was chemically activated to produce a novel material for malachite green disposal from liquid solutions. The adsorption kinetic, isotherms and the thermodynamic studies were conducted in batch experiment at optimum pH. Two models were analysed to study the kinetic data the Ho’s pseudo-second order model and the Lagergren’s pseudo-first order. The data has showed that the Ho’s model fits more with a (R2 = 0.983). For adsorption isotherms Freunlish and Langmuir models were studied, and the the results show that the Langmuir fits more with the highest R2. The thermodynamic study proved that the adsorption process is feasible and spontaneous, physical and reversible. Moreover, the positive value of ΔS° indicates that there is an increase in the randomness of the system of solid/solution interface during MG adsorption process by Opuntia ficus-indica’ s activated carbon.The activated carbon and raw material were analyzed by FTIR/ATR, SEM and EDX images. The infrared spectrums show that there were some changes in the functional groups surface. The chemical activation by the phosphoric acid leads to a peptization and dissolution of cellulose, hemicellulose, lignin, and polysaccharide in the raw material. However in the SEM images we can see clearly that the surface modification and the new pores is formed with the release of volatile matter by the H3PO4 activation process.