The interaction mechanism between eggshell calcium and endogenous silica in biomass during biochar modification,and its impact on phosphate adsorption performance and slow-release fertilizer characteristics,remains un...The interaction mechanism between eggshell calcium and endogenous silica in biomass during biochar modification,and its impact on phosphate adsorption performance and slow-release fertilizer characteristics,remains unexplored.This study investigates that high silica content in biomass(>6%)inhibits the decomposition of CaCO_(3)in eggshells during pyrolysis,reducing the formation of active calcium species(CaO and Ca(OH)_(2)),while moderate silica levels(4%-5%)promote the formation of CaSiO_(3),enhancing phosphorus adsorption without hindering Ca^(2+)activation.Adsorption studies reveal that the precipitation of Ca_(5)(PO_(4))_(3)(OH)resulting from the combination of CaO and Ca(OH)_(2)with phosphate is the primary and effective form for phosphorus removal in calcium-modified adsorbents,accompanied by Ca_(3)(PO_(4))_(2)·2H_(2)O precipitation formed by CaSi O_(3).Eggshell calcium-modified corn straw biochar(ECS)exhibited the highest adsorption capacity,reaching 123.3 mg/g,outperforming materials in previous studies.ECS also demonstrated excellent pH adaptability and selective phosphate removal.As a biochar-based phosphorus fertilizer,ECS-P exhibits high phosphorus extractability in formic acid(93.92%)but low water solubility(0.62%),with phosphorus release during the seven-day intermittent leaching experiment remaining between 0.53 to 0.875 mg/L.These results confirm its potential as a phosphorus cycling fertilizer.This study provides fundamental insights into optimizing biomass selection based on silica content for calcium modification,offering an efficient strategy for both phosphate recovery and slow-release fertilizer development.展开更多
【目的】对含腐殖酸增值磷酸二铵生产周期的碳足迹进行核算评估与研究分析,以期为增值肥料碳足迹研究提供科学依据和理论支撑。【方法】将产品工业生产过程(从“摇篮”到“大门”)定义为产品生产周期,基于生命周期法采用PAS 2050标准对...【目的】对含腐殖酸增值磷酸二铵生产周期的碳足迹进行核算评估与研究分析,以期为增值肥料碳足迹研究提供科学依据和理论支撑。【方法】将产品工业生产过程(从“摇篮”到“大门”)定义为产品生产周期,基于生命周期法采用PAS 2050标准对磷酸二铵和含腐殖酸增值磷酸二铵产品生产周期的碳足迹进行核算研究和评估分析。【结果】(1)以纯养分(P2O5)量计,普通磷酸二铵和含腐殖酸增值磷酸二铵产品生产周期的碳足迹分别为3636.73和3653.16 kg CO_(2)-eq·t^(-1),含腐殖酸增值磷酸二铵较普通磷酸二铵碳排放仅增加0.45%;以实物量(1 t肥料产品)计,普通磷酸二铵和含腐殖酸增值磷酸二铵产品生产周期的碳足迹分别为1672.90和1660.38 kg CO_(2)-eq·t^(-1),含腐殖酸增值磷酸二铵较普通磷酸二铵碳排放则降低了0.75%。二者碳足迹的差异只与腐殖酸增效剂的添加量相关。(2)合成氨碳足迹分别占磷酸二铵和含腐殖酸增值磷酸二铵产品生产周期碳足迹的67.87%和67.57%,是两种磷肥碳足迹的最大贡献者,而由添加腐殖酸增效剂所增加的碳足迹仅占含腐殖酸增值磷酸二铵产品生产周期碳足迹的0.45%。【结论】添加腐殖酸增效剂对磷酸二铵产品生产的碳排放影响很小,合成氨是磷酸二铵肥料产品生产周期碳足迹高低的最大影响因素。展开更多
基金supported by Hebei Key Laboratory of Mineral Resources and Ecological Environment Monitoring(No.HBMREEM202302)Tianjin Key Research and Development Science and Technology Project(Nos.24YFXTHZ00170 and 24YFXTHZ00050)。
文摘The interaction mechanism between eggshell calcium and endogenous silica in biomass during biochar modification,and its impact on phosphate adsorption performance and slow-release fertilizer characteristics,remains unexplored.This study investigates that high silica content in biomass(>6%)inhibits the decomposition of CaCO_(3)in eggshells during pyrolysis,reducing the formation of active calcium species(CaO and Ca(OH)_(2)),while moderate silica levels(4%-5%)promote the formation of CaSiO_(3),enhancing phosphorus adsorption without hindering Ca^(2+)activation.Adsorption studies reveal that the precipitation of Ca_(5)(PO_(4))_(3)(OH)resulting from the combination of CaO and Ca(OH)_(2)with phosphate is the primary and effective form for phosphorus removal in calcium-modified adsorbents,accompanied by Ca_(3)(PO_(4))_(2)·2H_(2)O precipitation formed by CaSi O_(3).Eggshell calcium-modified corn straw biochar(ECS)exhibited the highest adsorption capacity,reaching 123.3 mg/g,outperforming materials in previous studies.ECS also demonstrated excellent pH adaptability and selective phosphate removal.As a biochar-based phosphorus fertilizer,ECS-P exhibits high phosphorus extractability in formic acid(93.92%)but low water solubility(0.62%),with phosphorus release during the seven-day intermittent leaching experiment remaining between 0.53 to 0.875 mg/L.These results confirm its potential as a phosphorus cycling fertilizer.This study provides fundamental insights into optimizing biomass selection based on silica content for calcium modification,offering an efficient strategy for both phosphate recovery and slow-release fertilizer development.
文摘【目的】对含腐殖酸增值磷酸二铵生产周期的碳足迹进行核算评估与研究分析,以期为增值肥料碳足迹研究提供科学依据和理论支撑。【方法】将产品工业生产过程(从“摇篮”到“大门”)定义为产品生产周期,基于生命周期法采用PAS 2050标准对磷酸二铵和含腐殖酸增值磷酸二铵产品生产周期的碳足迹进行核算研究和评估分析。【结果】(1)以纯养分(P2O5)量计,普通磷酸二铵和含腐殖酸增值磷酸二铵产品生产周期的碳足迹分别为3636.73和3653.16 kg CO_(2)-eq·t^(-1),含腐殖酸增值磷酸二铵较普通磷酸二铵碳排放仅增加0.45%;以实物量(1 t肥料产品)计,普通磷酸二铵和含腐殖酸增值磷酸二铵产品生产周期的碳足迹分别为1672.90和1660.38 kg CO_(2)-eq·t^(-1),含腐殖酸增值磷酸二铵较普通磷酸二铵碳排放则降低了0.75%。二者碳足迹的差异只与腐殖酸增效剂的添加量相关。(2)合成氨碳足迹分别占磷酸二铵和含腐殖酸增值磷酸二铵产品生产周期碳足迹的67.87%和67.57%,是两种磷肥碳足迹的最大贡献者,而由添加腐殖酸增效剂所增加的碳足迹仅占含腐殖酸增值磷酸二铵产品生产周期碳足迹的0.45%。【结论】添加腐殖酸增效剂对磷酸二铵产品生产的碳排放影响很小,合成氨是磷酸二铵肥料产品生产周期碳足迹高低的最大影响因素。
