Biopolymeric flocculant extracted from potato residues using alkaline extraction method and its application in removing coal fly ash from ash-flushing wastewater generated from coal fired power plant

摘要

Ash-flushing wastewater generated by coal fired power plant generally contains high massive suspended coal fly ashes, which limit the recycling of ash-flushing wastewater and contaminate the environment due to the release of heavy metals from coal fly ashes. In this study, the Biopolymeric Flocculant extracted from Potato Residues (BFPR) under alkaline condition was applied to treat ash-flushing wastewater. The extraction conditions were optimized. The results showed that the highest yield of 58.77% BFPR was extracted from potato residues under the optimum condition: temperature 100 °C, potato residue concentration 42.09 g/L, extraction time 25.27 min, NaOH concentration 0.48 M and MgSO4?7H2O concentration 0.4 g/L. Gel permeation chromatography analysis indicated that the approximate molecular weight (MW) of BFPR was 4781 kDa. Fourier transform infrared spectroscopy indicated the presence of carboxyl, hydroxyl, and methoxyl groups in BFPR. Furthermore, BFPR showed good flocculating efficiency of 93.44% to ash-flushing wastewater when 8.3 mg/L BFPR was added, and thus achieved the recycling of ash-flushing wastewater.