Zhang H, Voroney R P, Price G W
J Environ Qual. 2017 Jul;46(4):889-896. doi: 10.2134/jeq2017.02.0043.
There have been limited studies of how pyrolysis temperature and activation processes alter the chemical properties of biochar and how these changes influence ammonium (NH), nitrate (NO), and phosphate (PO) sorption. This study compared the chemical properties of biochars and activated biochars (ActBC with steam and CO activation) produced by slow pyrolysis at 200 (BC200), 400 (BC400), 600 (BC600), 800 (ActBC200, ActBC400, ActBC600), and 850°C (sulfachar-S enriched biochar with steam activation). Quantitative solid-state C nuclear magnetic resonance spectroscopy and elemental analysis were used to study temperature and activation on biochar chemical properties. The sorption capacity of biochars for NH, NO, and PO were measured by batch sorption experiments. Nuclear magnetic resonance spectroscopy data showed that BC200 contained mainly aliphatic C compounds (86% of O-alkyl) belonging to cellulose and hemicellulose, whereas BC400 and BC600 composition was dominated by fused aromatic C structures, containing 81 and 97% aromatic C, respectively. Increasing pyrolysis temperatures decreased biochar total C but increased its cation exchange capacity, pH, and contents of total N and P, calcium, potassium, and magnesium. The BC200 released NO and PO, whereas sulfachar and ActBC200 sorbed significantly higher amounts NO and PO than BC600 by 83 and 96%, respectively, across aqueous solutions. Sulfachar and BC400 sorbed significantly greater amounts NH than did the other biochars. This study shows that production temperature significantly affects biochar chemical properties and that activation increases NO and PO sorption. These results suggest that activated biochar could be useful for sorbing soil N and P, thereby reducing leaching losses.
关于热解温度和活化过程如何改变生物炭的化学性质以及这些变化如何影响铵（NH）、硝酸盐（NO）和磷酸盐（PO）吸附的研究有限。本研究比较了在200（BC200）、400（BC400）、600（BC600）、800（ActBC200、ActBC400、ActBC600）和850°C（经蒸汽活化的富磺胺生物炭）下缓慢热解产生的生物炭和活化生物炭（蒸汽和CO活化的ActBC）的化学性质。采用定量固态碳核磁共振光谱和元素分析研究温度和活化对生物炭化学性质的影响。通过批量吸附实验测量生物炭对NH、NO和PO的吸附容量。核磁共振光谱数据表明，BC200主要包含属于纤维素和半纤维素的脂肪族碳化合物（86%的O-烷基），而BC400和BC600的组成主要由稠合芳族碳结构主导，分别含有81%和97%的芳族碳。热解温度升高会降低生物炭的总碳含量，但会增加其阳离子交换容量、pH值以及总氮、磷、钙、钾和镁的含量。BC200释放NO和PO，而在水溶液中，磺胺生物炭和ActBC200吸附的NO和PO量分别比BC600显著高83%和96%。磺胺生物炭和BC400吸附的NH量明显高于其他生物炭。本研究表明，生产温度显著影响生物炭的化学性质，活化可增加对NO和PO的吸附。这些结果表明，活化生物炭可用于吸附土壤中的氮和磷，从而减少淋失损失。
