Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, Southwest University, Chongqing, 400715, China.
College of Resources and Environment, Southwest University, Chongqing, 400715, China.
Environ Sci Pollut Res Int. 2020 Mar;27(7):7493-7503. doi: 10.1007/s11356-019-07355-5. Epub 2019 Dec 28.
In this study, a novel MgO-biochar composite was generated for nutrient recovery from biogas slurry using magnesium chloride (MgCl) and ammonia hydroxide (NH·HO). Biochar properties, including pH, CEC, pHpzc, magnesium content, surface area, and total pore volume (V), were evaluated. Moreover, the removal of NH and PO in both single and bi-solute system were investigated. Results indicated that NH·HO pretreatment and MgO-coating enhanced biochar pH, CEC, and pHpzc. Additionally, there were generally higher surface area and V in MgAWS. The maximum adsorption capacities for NH and PO, respectively, increased as WS (0.555 and 1.57 mg g) < MgWS (15.4 and 21.8 mg g) < MgAWS (17.5 and 31.3 mg g). Moreover, higher removal efficiencies were achieved in the bi-solute system, and over 25% and 90% of NH and PO, respectively, was removed from biogas slurry by MgASW. Mechanically, NH removal was mainly attributed to ionic exchange, while PO adsorption on MgO-coated biochars was due to electrostatic attraction and precipitation. Furthermore, the formation of struvite (MgNHPO·6HO) further enhanced N and P in the bi-solute system.
在这项研究中，使用氯化镁（MgCl）和氨水溶液（NH·HO）生成了一种新型的 MgO-生物炭复合材料，用于从沼气淤浆中回收营养物质。评估了生物炭的特性，包括 pH 值、CEC、pHpzc、镁含量、表面积和总孔体积（V）。此外，还研究了在单溶质和双溶质体系中 NH 和 PO 的去除情况。结果表明，NH·HO 预处理和 MgO 涂层提高了生物炭的 pH 值、CEC 和 pHpzc。此外，MgAWS 通常具有更高的表面积和 V。NH 和 PO 的最大吸附容量分别增加，WS（0.555 和 1.57 mg g）<MgWS（15.4 和 21.8 mg g）<MgAWS（17.5 和 31.3 mg g）。此外，在双溶质体系中实现了更高的去除效率，通过 MgASW 从沼气淤浆中分别去除了超过 25%和 90%的 NH 和 PO。从机械上讲，NH 的去除主要归因于离子交换，而 MgO 涂层生物炭上的 PO 吸附则归因于静电吸引和沉淀。此外，双溶质体系中形成了鸟粪石（MgNHPO·6HO），进一步增强了 N 和 P 的去除效果。
