Bioresource Technology 360 (2022) 127588 Available online 6 July 2022 0960-8524/© 2022 Elsevier Ltd. All rights reserved. Production of biochar from rice straw and its application for wastewater remediation  An overview Shin Ying Foong a, b, 1 , Yi Herng Chan c, 1 , Bridgid Lai Fui Chin d, i , Serene Sow Mun Lock e , Cia Yin Yee e , Chung Loong Yiin f, g , Wanxi Peng a , Su Shiung Lam b, a, h, * a Henan Province Engineering Research Center for Biomass Value-added Products, School of Forestry, Henan Agricultural University, Zhengzhou 450002, China b Pyrolysis Technology Research Group, Institute of Tropical Aquaculture and Fisheries (AKUATROP), Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia c PETRONAS Research Sdn. Bhd. (PRSB), Lot 3288 & 3289, off Jalan Ayer Itam, Kawasan Institusi Bangi, 43000 Kajang, Selangor, Malaysia d Department of Chemical and Energy Engineering, Faculty of Engineering and Science, Curtin University Malaysia, CDT 250, 98009 Miri, Sarawak, Malaysia e CO 2 Research Center (CO2RES), Department of Chemical Engineering, Universiti Teknologi PETRONAS, 32610 Seri Iskandar, Perak, Malaysia f Department of Chemical Engineering and Energy Sustainability, Faculty of Engineering, Universiti Malaysia Sarawak (UNIMAS), 94300 Kota Samarahan, Sarawak, Malaysia g Institute of Sustainable and Renewable Energy (ISuRE), Universiti Malaysia Sarawak (UNIMAS), 94300 Kota Samarahan, Sarawak, Malaysia h Sustainability Cluster, School of Engineering, University of Petroleum & Energy Studies, Dehradun, Uttarakhand 248007, India i Energy and Environment Research Cluster, Faculty of Engineering and Science, Curtin University Malaysia, CDT 250, 98009 Miri, Sarawak, Malaysia HIGHLIGHTS G R A P H I C A L ABSTRACT • Various synthesis and modifcation techniques of rice straw biochar are reviewed. • Pyrolysis is the most established and prominent method to produce biochar. • Acid-modifed biochar is effective for metal ions and organic compounds removal. • More understanding of the adsorption mechanism for other contaminants is needed. • Recyclability and stability of biochar are essential for wastewater treatment. A R T I C L E INFO Keywords: Rice straw Biochar Wastewater remediation Activation Adsorption ABSTRACT The valorization of biochar as a green and low-cost adsorbent provides a sustainable alternative to commercial wastewater treatment technologies that are usually chemical intensive and expensive. This review presents an in- depth analysis focusing on the rice straw-derived biochar (RSB) for removal of various types of contaminants in wastewater remediation. Pyrolysis is to date the most established technology to produce biochar. Subsequently, biochar is upgraded via physical, chemical or hybrid activation/modifcation techniques to enhance its adsorption capacity and robustness. Thus far, acid-modifed RSB is able to remove metal ions and organic compounds, while magnetic biochar and electrochemical deposition have emerged as potential biochar * Corresponding author. E-mail address: lam@umt.edu.my (S.S. Lam). 1 Co-frst authors. Contents lists available at ScienceDirect Bioresource Technology journal homepage: www.elsevier.com/locate/biortech https://doi.org/10.1016/j.biortech.2022.127588 Received 14 June 2022; Received in revised form 30 June 2022; Accepted 2 July 2022