Abstract:
Industrial sludge activated carbon was produced from paper mill, tannery and textile sludge for effective removal of Congo red dye from aqueous solution. Phosphoric acid (45%) for paper mill sludge and sulfuric acid (45%) for textile and tannery sludge was used as activating agents. Carbonization was carried out at 400 0c for three hours. The surface area of paper mill sludge activated carbon (734.6m2/g) was greater than that of tannery and textile sludge activated carbon ( 530.45m2/g) and (423.45m2/g), respectively. To investigate the surface chemistry of the industrial sludge activated carbon, Fourier transforms infrared spectroscopy (FTIR) analysis was carried due to acid activation, the synthesized industrial sludge activated carbon was in acidic range and the FTIR showed that the active site has acidic functional group. Results show that paper mill sludge activated carbon was found to have better removal efficiency than tannery and textile sludge activated carbon. Batch adsorption experiments were performed for the adsorption of the Congo red dye molecule from aqueous solution over the industrial sludge activated carbons.
The effect of various factors namely, solution pH, initial dye concentration ,contact time ,temperature and adsorbent dose were studied on percentage of congo red dye removal from aqueous solution. A maximum removal efficiency of 98.81, 93.67 and 89.78 % was obtained at pH of 4, initial dye concentration of 40mg/L and contact time of 60min onto paper mill, tannery and textile sludge activated carbon, respectively. Adsorption data were modeled with both the Langmuir and Freundlich isotherms. The kinetic models were also applied for the pseudo-first-order and pseudosecond-order .The experimental results have been fitted well by the Freundlich isotherm model with the higher correlation coefficients R2=0.9996,R2=0.9986 and R2=0.9955 for paper mill,tannery and textile sludge activated carbon respectively. Thus, indicates the adsorption capacity to the applicability of multilayer coverage of the dye on to the surface of the produced industrial sludge activated carbon. In addition, adsorption kinetics was determined using pseudo first order and pseudo second order models and it was found that the adsorption process follows the pseudo second order model over the industrial sludge activated carbons