Removal of basic dye from synthetic wastewater using sugarcane bagasse modified with propionic acid

AIM: The aim of the present study was to prepare natural adsorbent from sugar cane bagasse modified with propionic acid for the removal of basic dye ‘Methylene Blue’ from synthetic wastewater. OBJECTIVE: Adsorption experiments were performed to determine the optimum conditions of time, adsorbent dosage, adsorbent size, agitation speed, dye concentration and pH. MATERIAL AND METHODS: The sugarcane bagasse was procured and washed thoroughly with water. The bagasse was dried in sun for two days (Nevine 2008). It was then oven dried for 24 hours at 120 °C temperature (Hajira et al. 2012). The bagasse was crushed in the mixer until it turned fine powder and sieved to the sizes of 0.6, 0.3 and 0.15 mm. The efficiency of adsorption was influenced by various factors such as contact time, adsorbent dosage, size of the adsorbent, concentration of dye, pH and rpm. Each factor was optimized experimentally. BACKGROUND: The release of coloured waste water in to the natural streams such as rivers causes severe problems in the aquatic environment. The presence of dyes will absorb and reflect the sunlight entering the water thus hindering the process of photosynthesis in plants. This will reduce the water quality in natural streams and it also affects the human health. The dyes can also cause allergic diseases, skin irritations, cancer and mutations. RESULTS: The results indicated that the adsorbent showed good sorption potential and maximum dye removal was observed at pH 7.Within 8 minutes of operation about 81.5% of the dye was removed from the solution. The sorption curve was well fitted to the Langmuir model. The adsorption capacity of dye at optimum conditions was found to be 60 mg/L. Langmuir adsorption isotherms have been analysed and it gives high correlation factor (R2 > 0.98). Kinetic study shows that the adsorption process follows pseudo second order reaction with good correlation factor (R2 > 0.99).