The excessive application of phosphorus in agricultural lands leads to serious environmental issues. Efficient application is beneficial from an economic and environmental perspectives. Biochar can be used as a carrier for slow release of phosphate. However, its adsorption capacity is limited. In this work, biochar was prepared at different pyrolysis temperatures (350–550 °C). The biochar prepared at 550 °C had the highest adsorption capacity and was selected for modification by magnesium impregnation. Magnesium modification enhanced the adsorption capacity by 34% to a theoretical max adsorption capacity of 463.5 mg·g⁻¹. The adsorbed phosphate can be desorbed. The desorption was bi-phasic with fast- and slow-release fractions. The distribution of the phosphate fractions was pH dependent with slow release being most prominent in neutral conditions. Mg modified biochar can be used to recover phosphate and then used as a carrier for slow release of phosphate. The bi-phasic desorption behaviour is useful as the fast release fraction can provide the immediate phosphate needed during plant establishment, while the slow-release fraction maintains steady supply over extended periods.

中文翻译：

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改性硬木衍生生物炭以提高磷的吸附

磷在农田中的过量使用导致严重的环境问题。从经济和环境的角度来看，有效的应用是有益的。生物炭可用作缓慢释放磷酸盐的载体。但是，其吸附能力是有限的。在这项工作中，生物炭是在不同的热解温度（350–550°C）下制备的。在550°C下制备的生物炭具有最高的吸附能力，并选择通过镁浸渍进行改性。镁改性使吸附量提高了34％，达到理论最大吸附量463.5 mg·g ^-1。吸附的磷酸盐可以被解吸。解吸是双相的，具有快速释放和缓慢释放的部分。磷酸盐级分的分布取决于pH，在中性条件下缓释最为明显。镁改性生物炭可用于回收磷酸盐，然后用作缓慢释放磷酸盐的载体。双相解吸行为非常有用，因为快速释放级分可提供植物建立过程中所需的立即磷酸盐，而缓慢释放级分可在较长时间内保持稳定的供应。