Treatment of industrial ferric sludge through a facile acid-assisted hydrothermal reaction: Focusing on dry mass reduction and hydrochar recyclability performance

Xianbao Xu; Daan Zhu; Qiwei Jian; Xiaonuan Wang; Xiaohu Zheng; Gang Xue; Yanbiao Liu; Xiang Li; Gamal Kamel Hassan

doi:10.1016/j.scitotenv.2023.161879

Treatment of industrial ferric sludge through a facile acid-assisted hydrothermal reaction: Focusing on dry mass reduction and hydrochar recyclability performance

Sci Total Environ. 2023 Apr 15:869:161879. doi: 10.1016/j.scitotenv.2023.161879. Epub 2023 Jan 28.

Authors

Xianbao Xu¹, Daan Zhu¹, Qiwei Jian², Xiaonuan Wang¹, Xiaohu Zheng³, Gang Xue⁴, Yanbiao Liu¹, Xiang Li⁵, Gamal Kamel Hassan⁶

Affiliations

¹ College of Environmental Science and Engineering, State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua University, 2999 North Renmin Road, Shanghai 201620, China.
² School of Mechanical and Automotive Engineering, Shanghai University of Engineering Science, Shanghai 201620, China. Electronic address: janewill_cn@163.com.
³ Institute of Artificial Intelligence, Donghua University, 2999 North Renmin Road, Shanghai 201620, China.
⁴ College of Environmental Science and Engineering, State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua University, 2999 North Renmin Road, Shanghai 201620, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China.
⁵ College of Environmental Science and Engineering, State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua University, 2999 North Renmin Road, Shanghai 201620, China. Electronic address: lix@dhu.edu.cn.
⁶ Water Pollution Research Department, National Research Centre, 33El-Bohouth St. (Former El-Tahrir St.), Dokki, P.O. 12622, Giza, Egypt.

PMID: 36716871
DOI: 10.1016/j.scitotenv.2023.161879

Abstract

Large amounts of Fenton sludge and waste activated sludge (WAS) are mixed as ferric sludge (FS) in most industrial wastewater treatment plants. The treatment of such waste represents a challenge and quantity-dependent cost, so that a reliable way for FS waste reduction is required. In this study, we develop a facile acid-assisted hydrothermal treatment (HT) for the cost-efficient treatment of hazardous FS waste. Sulfuric acid was dosed at 0.25 mL/g dry solid (DS) to the HT process, which significantly increased the total solid mass reduction (TMR) by 25.1 % and dry mass reduction (DMR) by 104.4 %. The participation of sulfuric acid during the HT process changed the HT reaction pathway from dehydration to demethylation based on the analysis of the derivative thermogravimetric and Van Krevelen diagram. The addition of sulfuric acid improved the release of Fe from FS by 52.9 %, which contributed to the DMR. During the acid-assisted HT, Fe(III) was effectively reduced to Fe(II) within the produced hydrochar, which can be recycled for the Fenton reaction during the degradation of actual industrial wastewater such as pharmaceutical wastewater. Moreover, Sulfuric acid facilitated the generation of sulfonated hydrochar, which was efficient as an adsorbent for the complete removal of some metals such as Cu(II) - cation metal (98.8 %) and Cr(VI) - anion metal (99.9 %). This study firstly provides a novel and reliable approach for hazardous FS reduction and pointed out the recycling of hydrochar as the supplement for the Fenton reaction and adsorbents for some hazardous heavy metals.

Keywords: Hydrochar; Hydrothermal reaction; Pharmaceutical sludge; Sludge reduction; Sulfuric acid.