鸟粪石
化学
生物炭
吸附
磷
尿素氨挥发
肥料
磷酸盐
镁
挥发
氨
废水
铵
碱度
氮气
环境化学
无机化学
环境工程
热解
环境科学
生物化学
有机化学
作者
Yanqi Li,Meitao Tan,Fuzheng Gong,Qi Wu,Daocai Chi
标识
DOI:10.1016/j.scitotenv.2023.166575
摘要
Many studies have shown that magnesium modified biochar (MgBC) can recover nutrients from wastewater and be applied as an excellent slow-release fertilizer in farmland. However, the recovery products (NP-loaden MgBC), represented by struvite or magnesium phosphate, have a high degree of self-alkalinity, which may significantly increase the ammonia (NH3) volatilization in farmland. In this study, the optimal adsorption parameters, self-alkaline regulation process and co-adsorption mechanism of MgBC for ammonium ion (NH4+) and phosphate ion (PO43-) were studied through batch experiments. A field experiment was conducted with three treatments, including local conventional fertilization (N1B0) and the application of 5 t·ha-1 or 10 t·ha-1 NP-loaden MgBC in combination with local conventional fertilization (N1B1 and N1B2, respectively), to determine the impact of NP-loaden MgBC on NH3 volatilization, surface water c(NH4+-N) and pH. The results indicated that the maximum NH4+ and PO43- synergistic recovery of MgBC under the optimal adsorption parameters (dosage of 0.6 g·L-1; initial NH4+ and PO43- concentrations of 120 and 60 mg·L-1 and pH of 8) were 59.96 and 98.60 mg·g-1, respectively. Self-regulating alkaline MgBC maintained pH suitable for struvite, and precipitation mechanism controlled the adsorption. The presence of NP-loaden MgBC raised the pH levels in surface water during the basal fertilization stage and increased c(NH4+-N) in surface water during the topdressing stages. This, in turn, led to a significant increase in NH3 volatilization loss during the entire rice-growing period, with N1B1 and N1B2 experiencing a 23.87 % and 48.91 % increase respectively, compared to N1B0. Therefore, it is imperative to take into account the adverse impact of NP-laden MgBC on NH3 loss in paddy fields when considering its application in future field studies.
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