The photocatalytic degradation of lignin from simulated recycled paper mill effluent using nano titania

• Main Authors: Hermoso, Ria Angelica L., Montero, Shaira Sharmaine G.
• Format: text
• Language: English
• Published: Animo Repository 2009
• Subjects: Chemical engineering; Photocatalysis; Lignin; Pulp mills; Paper mills; Effluent quality; Paper industry
• Online Access: https://animorepository.dlsu.edu.ph/etd_honors/341
• Institution: De La Salle University

Lignin is contained in pulp and paper mill effluents, which is a major chemical oxygen demand (COD) component. In fact, the dark color of pulp and waste waters is due to the presence of residual lignin and of its degradation products. Several of these compounds remain in the water effluents and are severe water pollutants. Photocatalysis is a promising technology for lignin degradation. Photocatalysis is the combination of UV light and titania (TiO2) in a process. The study aims to compare commercial titania with nano-titania as well as to determine the effects of certain parameters such as pH, catalyst loading, lignin concentration and light source on the rate of lignin degradation. Activity of the titania for lignin degradation is determined using synthetic paper mill effluent made from commercial lignin. The lignin concentration was based from the lignin concentration of the actual wastewater collected by the researchers in a recycling paper mill effluent. The lignin concentration was found out to be 78.8ppm as determined by the Center for Pulp and Paper in Bandung, Indonesia. Also, the color of the wastewater was analyzed by CRL and gave a result of 250 PCU. The UV irradiation treatment was carried out using the existing photocatalytic batch reactor that is used by ARRPET researchers with 254 nm UV lamp. The analysis for the color removal efficiency of nanotitania was all determined by using the UV Vis Spectrophotometer. Activity test showed that nano-titania synthesized and calcined at 400C is the best type of catalyst showing the highest percentage degradation of ... after an hour of irradiation and a rate constant of 0.015min -1 using 254bnm UV lamp which is the most efficient light source. Using the best type of catalyst and light source under neutral conditions, the optimum catalyst dosage was found out to be 10g/L which resulted to a rate of constant of 0.019 min -1 and 71% degradation after an hour. The highest rate in the lignin degradation was also obtained when the pH was adjusted to 3. The rate of reaction for lignin degradation is also affected by the initial lignin concentration which showed that lower concentrations results to faster degradation. At 2 hours of undergoing the photocatalytic activity with the optimized conditions, 100% degradation was achieved. The optimum parameters were also applied to the actual wastewater and a complete degradation was reached at 3 hours of irradiation.