State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, P.O. Box 821, Nanjing, China; College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China.
State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, P.O. Box 821, Nanjing, China.
Environ Pollut. 2022 Nov 15;313:120175. doi: 10.1016/j.envpol.2022.120175. Epub 2022 Sep 14.
To develop more green, practical and efficient biochar amendments for acidic soils, chitosan-modified biochar (CRB) and alginate-modified biochar (ARB) were prepared, and their effects on promoting soil pH buffering capacity (pHBC) and immobilizing cadmium (Cd) in the paddy soils were investigated through indoor incubation experiments. The results of Fourier transform infrared spectroscopy and Boehm titration indicated that the introduction of chitosan and sodium alginate effectively amplified the functional groups of the biochar, and improved acid buffering capacity of the biochar. Since there was a plateau region between pH 4.5 and 5.5 in acid-base titration curve of the CRB, adding this biochar to acidic paddy soils apparently improved the pHBC and enhanced the acidification resistance of the paddy soils. The addition of ARB enhanced the reduction reactions during submerging and weakened the oxidation reactions during draining, thus retarded the decline of paddy soil pH during drainage. Furthermore, the pH of the paddy soils with ARB addition was higher at the end of draining, which reduced the activity of soil Cd. Considering the environmental sustainability of chitosan and sodium alginate and convenience of preparation method, biochars modified with these two materials provided alternatives for acidic paddy soil amelioration and heavy metal immobilization. However, the additional experiments should be conducted under field conditions to confirm practical application effects in the future.
为了开发更绿色、实用和高效的酸性土壤生物炭改良剂，制备了壳聚糖改性生物炭（CRB）和海藻酸钠改性生物炭（ARB），通过室内培养实验研究了它们对促进土壤 pH 缓冲能力（pHBC）和固定镉（Cd）的影响。傅里叶变换红外光谱和Boehm 滴定结果表明，壳聚糖和海藻酸钠的引入有效放大了生物炭的官能团，提高了生物炭的酸缓冲能力。由于酸碱滴定曲线中 CRB 的 pH 值在 4.5 和 5.5 之间存在一个平台区域，因此将这种生物炭添加到酸性稻田土壤中明显提高了 pHBC，并增强了稻田土壤的耐酸化能力。ARB 的添加增强了淹没过程中的还原反应，削弱了排水过程中的氧化反应，从而减缓了排水过程中稻田土壤 pH 值的下降。此外，添加 ARB 的稻田土壤在排水结束时的 pH 值更高，降低了土壤 Cd 的活性。考虑到壳聚糖和海藻酸钠的环境可持续性以及制备方法的便利性，这两种材料改性的生物炭为酸性稻田土壤改良和重金属固定提供了替代方案。然而，未来应在田间条件下进行更多的附加实验，以确认实际应用效果。
