SIMULTANEOUS ADSORPTION OF ANILINE AND NITROBENZENE BY GRANULAR ACTIVATED CARBON IN PACKED BED

Abstract

Waste water has been found to contain small amounts of a large number of synthetic organic compounds such as phenols, pesticides, herbicides, aliphatic and aromatic hydrocarbons, and their halogen derivatives, dyes, surfactants, organic sulfur compounds, ethers, amines, and nitro compounds. So, in order to maintain the permissible limit, organic pollutants have to be removed from the effluent stream before being discharge to the surface water. In this work, the process of multicomponent adsorption for the removal of aniline (AN) and nitrobenzene (NB) by granular activated carbon (GAC) was studied in batch and continuous mode. For single component batch study, the adsorption uptake of AN and NB increases and percent removal decreases with increasing initial adsorbate concentration. The single component equilibrium adsorption uptake of AN and NB is best fitted by BET isotherm model. For multicomponent batch adsorption study of AN and NB from binary mixture, the equilibrium adsorption uptake of AN decreases with increasing NB concentrations and vice versa. The equilibrium uptake of simultaneous adsorption of AN and NB from a binary mixture is well represented by extended Langmuir model. The simultaneous adsorption behavior of aniline (AN) and nitrobenzene (NB) mixtures from a synthetic aqueous solution over carbonaceous material surfaces GAC has been studied under dynamic conditions in a packed bed column. The effects of sorbent bed length (Z = 30, 45 and 60 cm), bed diameter (D = 2, 2.54 and 4 cm), and initial concentration (Co = 500-1000 mg/lit) on the adsorption characteristics of aniline and nitrobenzene were investigated. It has been seen that column performance improved with increasing Z and decreasing Q. In Different adsorption capacities were found for the two organics. Specifically, it was higher for iii nitrobenzene, and quite lower for the case of aniline. Taguchi's optimization method of design of experiments was used to study the effect of each parameter (flow rate, bed height and bed diameter) at three levels on the total amount of solutes adsorbed on GAG (q,0,, mg/g). The q€0, value (4.199 mg/g) coming from confirmation experiment is almost same with the predicted q,0, value (4.17 mg/g) which was coming from Taguchi's optimization method. A proposed new breakthrough model was found to well-predict the breakthrough time for simultaneous adsorption of AN and NB in packed bed.