Anaerobic Granular Sludge Adsorption Removal Of Dyes From Aqueous

In recent year, application of biosorption for the treatment of dye-bearing wastewater has been focused because of its high efficiency, high speed, wide spectrum of applicability and tolerance to bio-toxicity. This work use anaerobic granular sludge treat dye -bearing wastewater. The main points obtained in this study are summarized as follows:(1) The performance of native and heat-treated anaerobic granular sludge in removing of malachite green (MG) from aqueous solution was investigated with different conditions, such as pH, ionic strength, initial concentration and temperature. The maximum biosorption was both observed at pH 5 on the native and heat-treated anaerobic granular sludge. The ionic strength had negative effect on MG removal. Kinetic studies showed that the biosorption process followed pseudo-second-order Intraparticle diffusion model could well illuminate adsorption process and faster adsorption rate of native anaerobic granular sludge than heat-treated anaerobic granular sludge. The equilibrium data were analyzed using Langmuir and Freundlich model, and well fitted Langmuir model. Q~0 for native and heat treated anaerobic granular sludge is 72.36 mg/g and 119.19 mg/g at 60℃, respectively. Heat treated anaerobic granular sludge have lager biosorption capacity than native anaerobic granular sludge. The negative values of△G~0 and△H~0 suggested that the interaction of MG adsorbed by native and heat-treated anaerobic granular sludge was spontaneous and exothermic. Desorption studies revealed that MG could be well removed from anaerobic granular sludge by 1% (v/v) of HCl-alcohol solution.(2) This study reports the possibility of enhancing Acid Red 18 (AR18) biosorption capacity of anaerobic granular sludge via its cross-linking with polyethylenimine (PEI). X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) study revealed that the PEI modification introduced a large number of amino groups on the surface of anaerobic granular sludge, and the amino groups played an important role in the adsorption of dye molecular. The color removal was decreased with the increasing of pH. The maximum color removal was observed at pH 2. Analysis of sorption data using a Boyd plot confirms the surface diffusion as the rate-limiting step for the dye concentration ranges studied in the present investigation. The equilibrium data were well fitted Langmuir model, with a maximum Acid Red 18 uptake of 520.52 mg/g. Various thermodynamic parameters, such as△G~0,△H~0, were calculated, which indicated that the present system was spontaneous and endothermic process.(3) Four major functional groups: carboxyl, amino, hydroxyl and phosphate on the anaerobic granular sludge surface in biosorption different dyes. This functional groups in anaerobic granular sludge were chemically modified individually to determine their contribution to the biosorption of dyes. It was found that biosorption of dyes was influenced by the functional groups in the anaerobic granular sludge .