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In this study, a novel and low-cost seawater-modified biochar (SBC) was fabricated via the pyrolysis of fir woodwaste followed by co-precipitation modification using seawater as the Ca/Mg source. The co-precipitation pH was a vital factor during modification, and the optimal pH was 10.50 according to calculations using PHREEQC 2.5 and experiments. The characterizations indicated that Ca and Mg were loaded on the SBC as irregular CaCO3 and nanoflake-like Mg(OH)(2), respectively, with the latter dominating. The SBC exhibited a high maximumadsorption capacity of 181.07 mg/g for phosphate, calculated using the Langmuir model, excellent adsorption performance under acidic and neutral conditions (pH = 3.00-7.00), and remarkable selectivity against Cl-, NO3-, and SO42-. The presence of HCO3- promote d adsorption. The mechanisms behind phosphate adsorption involved electrostatic attraction, ligand exchange, precipitation, and inner-sphere complexation. Mg, rather than Ca, was served as the main adsorptive sites for phosphate. Additionally, the feasibility of treating real-world wastewater was tested in batch (using SBC powders) and fixed-bed column (using SBC granules) experiments. The results indicate that the SBC powders could reduce the phosphate concentration from 1.26 mg P/L to below 0.5 mg P/L at a low dose of 0.50 g/L, and the SBC granules exhibited a high removal efficiency with excellent recyclability; the capacity still remained at 78.92% of the initial capacity after five adsorption-desorption runs. Furthermore, the modification process almost did not increase the production cost of the SBC, which was estimated to be 0.41 $/kg. Our results demonstrate that seawater is a low-cost and efficient modifier for biochar modification, and the resultant SBC demonstrates great potential for treating actual phosphate-containing wastewater.
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SCIENCE OF THE TOTAL ENVIRONMENT
ISSN: 0048-9697
Year: 2022
Volume: 824
9 . 8
JCR@2022
8 . 2 0 0
JCR@2023
ESI Discipline: ENVIRONMENT/ECOLOGY;
ESI HC Threshold:64
JCR Journal Grade:1
CAS Journal Grade:1
Cited Count:
WoS CC Cited Count: 24
SCOPUS Cited Count: 29
ESI Highly Cited Papers on the List: 0 Unfold All
WanFang Cited Count:
Chinese Cited Count:
30 Days PV: 2
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