Open AccessRemoval of Fluoride from Water Using a Calcium-Modified Dairy Manure–Derived Biochar
Author(s) -
Anna Rose Wallace,
Chunming Su,
YongKeun Choi,
Eunsung Kan,
Wenjie Sun
Publication year - 2020
Publication title -
journal of environmental engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.438
H-Index - 95
eISSN - 1943-7870
pISSN - 0733-9372
DOI - 10.1061/(asce)ee.1943-7870.0001812
Subject(s) - biochar , fluoride , chemistry , sorption , manure , adsorption , calcium , langmuir , fertilizer , freundlich equation , environmental chemistry , langmuir adsorption model , precipitation , inorganic chemistry , nuclear chemistry , agronomy , organic chemistry , pyrolysis , physics , meteorology , biology
This study investigated the removal of fluoride from water using a calcium-modified dairy manure-derived biochar (Ca-DM500). The Ca-DM500 showed a 3.82 - 8.86 times higher removal of fluoride from water than the original (uncoated) manure-derived biochar (DM500). This is primarily attributed to strong precipitation/complexation between fluoride and calcium. The Freundlich and Redlich-Peterson sorption isotherm models better described the experimental data than the Langmuir model. Additionally, the removal kinetics were well described by the intraparticle diffusion model. The Ca-DM500 showed high reactivity per unit surface area [0.0001, 0.03, 0.16 mg F per m 2 for Douglas fir-derived biochar (DF-BC), DM500. and Ca-DM500, respectively] for retention of fluoride reflecting the importance of surface complexation. The copresence of anions reduced removal by Ca-DM500 in the orderSO 4 2 - ≈ PO 4 3 - > NO 3 - . The sorption behavior of fluoride in a continuous fixed-bed column was consistent with the Thomas model. Column studies demonstrated that the Ca-DM500 shows a strong affinity for fluoride, a low release potential, and a stable (unreduced) removal capacity through regeneration and reuse cycles.