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華中農業大學胡紅青教授團隊通過盆栽實驗，評估三種鈍化劑在不同用量時固定鎳的效率以及土壤中各形態Ni的含量，並利用Langmuir和Freundlich等溫線測定了Ni的吸附行為。相關成果發表於Chemosphere（IF=5.778）。
論文第一作者為華中農業大學Umeed Ali博士，通訊作者為胡紅青教授，Muhammad Shaaban、Saqib Bashir、高瑞麗、付慶靈、朱俊參與了試驗研究，課題得到國家科技支撐計劃（2015BAD05B02）資助。
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•Rice straw (RS) and its biochar (BI) and calcite (CC) were fabricated and applied for Ni remediation in acidic soil.
•BI was more effective for Ni passivation with 93.9% reduction of bioavailable Ni.
•Good dispersion and extra adsorption sites in BI facilitated Ni binding.
Although rice straw (RS), biochar (BI) and calcite (CC) have proved to be effective immobilizing agents in acidic contaminated soil, we lack up-to-date scientific data regarding nickel (Ni) fractionation in soil and removal capacity in water. Therefore, an incubation study was undertaken to investigate the efficacy of RS, BI and CC with three application rates (0, 1 and 2%) of RS, BI and CC on the immobilization of Ni in polluted soil. Various extraction techniques were carried out: sequential extraction procedure, the European Community Bureau of Reference (BCR), extraction with CaCl2,and the toxicity characteristics leaching procedure (TCLP) techniques. Additionally, Ni sorption behavior was determined using the Langmuir and Freundlich isotherms. Results showed that adding all amendments into Ni contaminated acidic soil, enhanced soil pH, reduced the exchangeable fraction of Ni by 48%–55%, 59%–71% and 58%–66.3%, when RS, BI and CC were applied at 1% and 2% rates, respectively. According to the Langmuir adsorption isotherm results, the maximum sorption capacity was recorded using 2747 mg kg−1 in 2% CC amended soil. However, biochar exhibited the maximum Ni sorption capacity (13348 mg kg−1), due to its porous structure, larger surface area, and having more functional groups. Furthermore, the results of FTIR, SEM and zeta potential techniques confirmed that the immobilization and biochar’s capacity to remove Ni were more effective when compared to other immobilizing agents.
農田土壤鎳可以通過食物鏈富集，給糧食安全帶來了巨大威脅。研究表明，地表水和土壤中的容許鎳濃度分別為0.005 mg L-1和100 mg kg-1，因此需向汙染土壤和水體中添加經濟有效的鈍化劑來降低其有效性和移動性。雖有大量研究表明水稻秸稈(RS)、生物炭(BI)和方解石(CC)能有效鈍化和吸附土壤中的重金屬，但是關於RS、BI和CC三種鈍化劑的效率比較，以及三種鈍化劑在Ni溶解度和吸附機理方面的研究還鮮見報導。因此，該論文通過盆栽實驗，評估三種鈍化劑RS、BI和CC用量為0、1%、2%時固定鎳的效率以及土壤中各形態Ni的含量。運用逐步萃取、BCR連續提取、CaCl2提取、TCLP毒物浸提法等技術浸提土壤中Ni，並利用Langmuir和Freundlich等溫線測定Ni的吸附行為。結果表明：在Ni汙染的酸性土壤中加入1%和2%的RS、BI和CC均能增加土壤的pH，且CC處理增加最多；降低土壤中可交換態Ni的含量分別為48%-55%、59%-71%、58%-66.3%，其中BI能有效地降低酸溶態、CaCl2提取態、TCLP提取態Ni的含量，促進Ni向殘渣態轉化。添加2%的RS、BI和CC增加殘渣態Ni含量分別為19%、21.8%、15%。根據Langmuir吸附等溫曲線，與對照相比，添加2% CC對Ni2+的最大吸附量達到2747 mg/kg。由於生物炭具有發達的孔隙，表面積大，豐富的功能基團等特徵，施用後具有最大的Ni吸附量。此外，FTIR、SEM和Zeta電位技術證明了水稻秸稈生物炭的固定和去鎳能力比其他鈍化劑更有效。
論文引用格式：
Ali U, Shaaban M, Bashir S, et al. Rice straw, biochar and calcite incorporation enhance nickel (Ni) immobilization in contaminated soil and Ni removal capacity[J]. Chemosphere, 2020, 244, 125418.
DOI：
10.1016/j.chemosphere.2019.125418
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