title: Recovery of high purity sulfuric acid from the waste acid in toluene nitration process by rectification.
abstract: Waste sulfuric acid is a byproduct generated from numerous industrial chemical processes. It is essential to remove the impurities and recover the sulfuric acid from the waste acid. In this study the rectification method was introduced to recover high purity sulfuric acid from the waste acid generated in toluene nitration process by using rectification column. The waste acid quality before and after rectification were evaluated using UV-Vis spectroscopy, GC/MS, HPLC and other physical and chemical analysis. It was shown that five nitro aromatic compounds in the waste acid were substantially removed and high purity sulfuric acid was also recovered in the rectification process at the same time. The COD was removed by 94% and the chrominance was reduced from 1000° to 1°. The recovered sulfuric acid with the concentration reaching 98.2 wt% had a comparable quality with commercial sulfuric acid and could be recycled back into the toluene nitration process, which could avoid waste of resources and reduce the environmental impact and pollution.
authors.affiliation: Department of Environmental Engineering, Peking University, The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Song
authors.forename: Qingqiang
authors.initials: Q
authors.lastname: Meng
authors.forename: Fan
authors.initials: F
authors.lastname: Shu
authors.forename: Zhengfang
authors.initials: Z
authors.lastname: Ye
mesh_terms: D002617:Chemical Industry; D055772:Green Chemistry Technology / Q000379:methods*; D007220:Industrial Waste; D058465:Nitrification; D059027:Recycling; D013464:Sulfuric Acids / Q000737:chemistry*; D014050:Toluene / Q000737:chemistry*
chemical_list: D007220:Industrial Waste; D013464:Sulfuric Acids; D014050:Toluene; C033158:sulfuric acid