UTILIZATION AND REMOVAL OF SURFACTANT AND DYES FROM THE WASTE WATER BY CHEMICAL AND PHYSICAL METHODS

Abstract

The control of water pollution has become of increasing interests because it is associated with the life of human beings, animals and the land which is irrigated with it. Water pollution has many dimensions and types but pollution due to industrial wastes is commonly metal pollution and chemical pollution. The present study emphasizes the water pollution and composites present in waste water like dyes and surfactants. Dyes are the main component of the dyeing industries so the effluent carrying high content of dyes along with other composites. It is quite difficult to remove dyes from effluents since most of them are stable to light, heat and oxidizing agents and they are biologically non-degradable also. Whereas the surfactants are the major part of every washing and cleaning agents like soaps, washing powder, dish washing bars, toothpastes and widely used in textile industry as softener. So both dyes and surfactants are the major constituent of domestic and industrial waste water. The treatment of contaminated waste water is necessary before it enter into the stream, lake, river or sea. The disposal of wastes containing dyes and surfactants into receiving water bodies effects on the values of biological oxygen demand (BOD) and chemical oxygen demand (COD) which resulted toxicity of aquatic life. In the current study by employing physical and chemical treatment methods utilization and removal of surfactant and dyes were carried out. The physical treatment method like adsorption technique was adopted by using natural materials and their modified surfaces for the removal of dyes and surfactant. The physical treatment method is beneficial for the removal and the regeneration of adsorbed substances. It is also economical and low cost method and can be employed on industrial scale before the disposal of waste into the stream and other reservoirs. The efforts were done by developing a model system for the removal of surfactant Cetylpyridinum Chloride (CPYCl) and dyes Malachite Green 11

(MG), Methylene blue (MB), Fast Green (FG) from aqueous solution by adopting batch adsorption method. The Cetylpyridinum Chloride (CPYCl) is the main constituent of daily washing powder and the dyes Malachite Green (MG) and Methylene blue (MB) are used in textile and paper industries and Fast Green (FG) dye widely used in food industries. The adsorbents were used for the removal of surfactant and dyes are raw Charcoal (RC), marine Algea like Ulva Lactuca (UL) and Sargassum Muticum (SM), Used Black tea (UBT), and impregnated used black tea (IM-UBT). Raw Charcoal was prepared from coconut dry shells, the algae Ulva Lactuca (UL) and Sargassum Muticum (SM) were collected from sea shore near the Clifton beach of Arabian Sea while Used Black tea (UBT) were collected from tea canteens as it is waste material after making tea and used for adsorption purposes. The modified surface of UBT were prepared by impregnation technique and their nano composites were prepared by impregnation with lead nitrate Pb(NO3)2. The batch adsorption experiments were run and effect of amount of adsorbents, concentration of adsorbate, contact time and temperature were investigated. Spectrophotometric technique was adopted for the measurement of concentration of dyes before and after adsorption. The adsorption data were fitted in the adsorption models like Langmuir, Freundlich and Dubinin- Radushkevich adsorption isotherm equations and the values of their respective constants were evaluated. Thermodynamic parameters such as (ΔG) free energy, (ΔH) enthalpy, and (ΔS) entropy of the system were calculated. Mean free energy of sorption (Es) was also estimated in order to get the clear picture of energy exchange between the adsorbate and adsorbent using D-R adsorption isotherm equation. The values of % removal show that adsorption of surfactant (CPYCl) and dyes (MG), (MB) and (FG) on the natural and modified adsorbents show about 70% - 80% removal tendency.

The chemical treatment method was adopted for the decoloration of dye effluent by the photoreduction method. The reduction kinetic was studied for all the dye systems but fast green (FG) show dominating results. It is evenly widely used for domestic and industrial purposes and also it is a representative of its acidic group dyes. The rate of the reaction was determined by varying concentration and temperatures of dye, surfactant and base (NaOH) at 303K to 323 K at the step of ± 5 °C. It was observed that the reduction followed pseudo first-order kinetics with respect to dye, surfactant, and OH– ion concentration .The mechanism for the photo bleaching of the dye has been proposed and well confirmed by the data simulation procedure. The activation parameters of the reaction like entropy of activation (ΔS) and free energy of activation (ΔG) showed the extremely solvated states of transient complex which was less disorderly arranged than the oxidized form of dye, whereas energy of activation Ea values reflects a high amount of energy required for the reduction of dye with surfactant cetylpyridinum chloride. The % decolorations of dyes were obtained about 70 to 80%. It was concluded that if the effluent contains acidic dyes and the cationic surfactant simultaneously, the dye will reduced by the surfactant and in this manner that surfactant in waste will also be utilized to reduce the harmful effects of dyes. It is an economical and cost effective method to utilize waste material for the purification of effluent also we can regenerate these adsorbents for the further treatment process. By employing impregnation technique nano composites were prepared from waste material and they show better adsorption tendency as compared to commercial adsorbents. The purification of waste water was carried out by employing physical method like adsorption and chemical method by reduction kinetics technique so we can simulate the model for the recycling of solid -liquid waste and we save the environment with harmful pollutants.