Study on preparation of water hyacinth-based activated carbon for pulp and paper mill wastewater treatment

Mulberry pulp and paper mills produce high chemical- and organic matter containing waste water in Thailand. Many of the mills are not equipped with wastewater treatment unit; their untreated effluent is directly discharged into recipient water resources. The effluent constituents are well recognized as acute and chronic pollutants that are hazardous to the environment. The present study aimed to investigate the utilization of an activated carbon from a low-cost material and to examine its adsorption performance using batch and fixed-bed adsorption. Water hyacinth was used as a raw material for activated carbon production via a chemical activation method. The results showed that water hyacinth-based activated carbon (WHAC) provided a high surface area of 912-1,066 m2g(-1) and exhibited micropore structure. Based on the Freundlich fit, the maximum adsorption capacity of COD and color was 4.52 mgg(-1) and 13.57 Pt-Cog(-1), respectively. The fixed bed adsorption provided maximum removal efficiency of 91.70 and 92.62% for COD and color, respectively. A continuous adsorption data agreed well with the Thomas kinetic model. In summary, water hyacinth can be used as a low-cost material for activated carbon production with high removal efficiency of COD and color for pulp and paper mill wastewater treatment.