Sludge-based biochar was first modified for the adsorption of phosphorus from aqueous solution. This study is to modify sludge-based biochar (SBC) via peroxidation with nitric acid and impregnation with ferrous ions to obtain a high adsorption capacity for phosphorus (P). The P adsorption capacity of the modified sludge biochar (M-SBC) was increased to 9.79 mg/g, a value almost 40 times higher than that of the original biochar. Among the adsorption parameters studied, pH was found to be particularly important to P adsorption. After modification, the point of zero charge of the M-SBC occurred at pH 6. The isotherms of P adsorption on M-SBC obeyed the Freundlich equation. An analysis of the adsorption thermodynamics indicated that the process of P adsorption on M-SBC was spontaneous and endothermic, increased the degree of disorder, and involved chemisorption. The main mechanisms of P adsorption were surface precipitation and electrostatic attraction.

首先对基于污泥的生物炭进行了改性，以吸附水溶液中的磷。这项研究旨在通过硝酸过氧化和亚铁离子浸渍来改性基于污泥的生物炭（SBC），以获得对磷（P）的高吸附能力。改性污泥生物炭（M-SBC）的P吸附能力增加到9.79 mg / g，几乎是原始生物炭的40倍。在研究的吸附参数中，发现pH对P吸附特别重要。修饰后，M-SBC的零电荷点出现在pH值为6的情况下。P在M-SBC上的吸附等温线符合Freundlich方程。吸附热力学分析表明，M-SBC上的P吸附过程是自发的，吸热的，无序程度增加，并涉及化学吸附。磷吸附的主要机理是表面沉淀和静电吸引。