Preparation and Modification of Biochar and Application of Modified Biochar in Remediation of Contaminated Soil

Abstract

Biochar, with its unique properties including high specific surface area, has become an increasingly popular material in the field of environmental restoration. The present paper provides a systematic analysis and summary of the preparation, characterization, and modification strategies for traditional biochar, as well as its application in soil remediation. A variety of different methods have been developed and applied to produce biochar, of which the most commonly used method is pyrolysis which consists mainly of slow and fast pyrolysis, followed by hydrothermal carbonization. Biochar can be modified by the injection of acids, alkalis, metal oxides, metal ions, steam and gas. On this basis, the utilization of modified biochar in soil restoration and remediation was further analyzed. Modified biochar breaks through various limitations such as the instability of traditional biochar, and performs an irreplaceable function not only in adsorption of organic pollutants, but also in the removal of heavy metal pollution. Additionally, managers also need to avoid the potential risk of secondary contamination by releasing polycyclic aromatic hydrocarbons (PAHs) into the surrounding environment. The aim of this paper is to explore the basic properties and preparation methods of biochar, to identify its restrictions and different modification methods, to highlight the contribution that modified biochar can make to today's sustainability-focused world, and to lay the groundwork for future research.