Modified and pristine biochars for remediation of chromium contamination in soil and aquatic systems.


El-Naggar A., Mosa A., Ahmed N., Niazi N. K. , Yousaf B., Sarkar B., ...More

Chemosphere, vol.303, no.Pt 1, pp.134942, 2022 (Peer-Reviewed Journal) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 303 Issue: Pt 1
  • Publication Date: 2022
  • Doi Number: 10.1016/j.chemosphere.2022.134942
  • Journal Name: Chemosphere
  • Journal Indexes: Science Citation Index Expanded, Scopus, Academic Search Premier, PASCAL, Aerospace Database, Aqualine, Aquatic Science & Fisheries Abstracts (ASFA), Artic & Antarctic Regions, BIOSIS, Biotechnology Research Abstracts, CAB Abstracts, Chemical Abstracts Core, Chimica, Communication Abstracts, Compendex, EMBASE, Environment Index, Food Science & Technology Abstracts, Geobase, Greenfile, MEDLINE, Metadex, Pollution Abstracts, Public Affairs Index, Veterinary Science Database, Civil Engineering Abstracts
  • Page Numbers: pp.134942
  • Keywords: Biochar modification, Charcoal, Immobilization, Sorption, Toxic trace elements, Hexavalent chromium, ZERO-VALENT IRON, HEXAVALENT CHROMIUM, HEAVY-METALS, CR(VI) REMOVAL, PLANT SYSTEM, REDUCTION, ADSORPTION, SORPTION, WATER, BIOAVAILABILITY

Abstract

Chromium (Cr) contamination in soil and water poses high toxicity risks to organisms and threatens food and water security worldwide. Biochar has emerged as a promising material for cleaning up Cr contamination owing to biochar's strong capacity to immobilize Cr. This paper synthesizes information on biochar modification for the efficient remediation of Cr contamination in soil and water, and critically reviews mechanisms of Cr adsorption on pristine and modified biochars. Biochar modification methods include physical activation via ball milling or ultraviolet irradiation, chemical activation via magnetization, alkali/acid treatment, nano-fabrication or loading of reductive agents, and biological activation via integrating biochars with microorganisms and their metabolites. Modified biochars often have multi-fold enhancement in Cr adsorption/reduction capacity than pristine biochars. Iron (Fe)-supported magnetic biochars have the most promising Cr removal abilities with high reusability of the biochars. Pre-pyrolysis modification with Fe could load Fe3O4 micro-/nanoparticles on biochars, and increase the surface area and electrostatic attraction between chromate anions and biochar surfaces, and reduce Cr(VI) to Cr(III). Post-pyrolysis modification could enrich oxygen-containing functional groups such as C--O and -OH on biochar surfaces and promote Cr reduction and adsorption. Future research directions for Cr advanced biochar are discussed in this review.