Back to Search
Start Over
Unraveling biochar surface area on structure and heavy metal removal performances of carbothermal reduced nanoscale zero-valent iron.
- Source :
- Journal of Bioresources & Bioproducts; Nov2023, Vol. 8 Issue 4, p388-398, 11p
- Publication Year :
- 2023
-
Abstract
- Carbothermal reduction using biochar (BC) is a green and effective method of synthesizing BC-supported nanoscale zero-valent iron (nanoFe<superscript>0</superscript>) composites. However, the effect of BC surface area on the structure, distribution, and performance such as the heavy metal uptake capacity of nanoFe<superscript>0</superscript> particles remains unclear. Soybean stover-based BCs with different surface areas (1.7 − 1 472 m²/g) were prepared in this study. They have been used for in-situ synthesis BCs-supported nanoFe<superscript>0</superscript> particles through carbothermal reduction of ferrous chloride. The BCs-supported nanoFe<superscript>0</superscript> particles were found to be covered with graphene shells and dispersed onto BC surfaces, forming the BC-supported graphene-encapsulated nanoFe<superscript>0</superscript> (BC-G@Fe<superscript>0</superscript>) composite. These graphene shells covering the nanoFe<superscript>0</superscript> particles were formed because of gaseous carbon evolved from biomass carbonization reacting with iron oxides/iron salts. Increasing BC surface area decreased the average diameters of nanoFe<superscript>0</superscript> particles, indicating a higher BC surface area alleviated the aggregation of nanoFe<superscript>0</superscript> particles, which resulted in higher heavy metal uptake capacity. At the optimized condition, BC-G@Fe<superscript>0</superscript> composite exhibited uptake capacities of 124.4, 121.8, 254.5, and 48.0 mg/g for Cu<superscript>2+</superscript>, Pb<superscript>2+</superscript>, Ag<superscript>+</superscript>, and As<superscript>3+</superscript>, respectively (pH 5, 25 °C). Moreover, the BC-G@Fe<superscript>0</superscript> composite also demonstrated high stability for Cu<superscript>2+</superscript> removal from the fixed-bed continuous flow, in which 1 g of BC-G@Fe<superscript>0</superscript> can work for 120 h in a 4 mg/L Cu<superscript>2+</superscript> flow continually and clean 28.6 L Cu<superscript>2+</superscript> contaminated water. Furthermore, the BC-G@Fe<superscript>0</superscript> composite can effectively immobilize the bioavailable As<superscript>3+</superscript> from the contaminated soil, i.e., 5% (w) of BC-G@Fe<superscript>0</superscript> composite addition can immobilize up to 92.2% bioavailable As<superscript>3+</superscript> from the contaminated soil. [ABSTRACT FROM AUTHOR]
- Subjects :
- BIOCHAR
HEAVY metals
SOIL remediation
SORPTION
ZERO-valent iron
Subjects
Details
- Language :
- English
- ISSN :
- 20972415
- Volume :
- 8
- Issue :
- 4
- Database :
- Complementary Index
- Journal :
- Journal of Bioresources & Bioproducts
- Publication Type :
- Academic Journal
- Accession number :
- 173903332
- Full Text :
- https://doi.org/10.1016/j.jobab.2023.06.003