Abstract:

In order to seek a reasonable way for the utilization of edible fungi residue and develop a green and high-efficient adsorbent for the treatment of phosphorus-containing wastewater, mushroom residue (MR) was employed as a raw material to prepare biochars under 800, 900 and 1000℃, and the adsorption capability of the biochars was investigated. It is found that the biochars are abundant in minerals, such as K, Na, Ca and Mg. Particularly, the content of Ca in the biochars are 4328.43—4919.38 mmol/kg and the Ca existed in biochars are mainly in the form of CaCO₃. The increase of pyrolysis temperature results in the decomposition of part of CaCO₃ into CaO. Moreover, the biochars possess relatively higher pH_pzc of 11.86—12.04, developed pore structure with a specific surface area of 167.56—223.80 m²/g and abundant surface functional groups, such as C\stackrel{}{̿}O, C\stackrel{}{̿}C, C—O, Ca—O, as well. The adsorption of phosphate onto the biochars is in the order of MR-800C< MR-900C< MR-1000C and the adsorption processes can be well fitted by Langmuir model and pseudo-second-order model, indicating that the adsorption of phosphate using the bicohars are dominated by a chemical and homogeneous monolayer adsorption process. The theoretical maximum adsorption capacity of MR-800C, MR-900C and MR-1000C calculated from the Langmuir model are 104.17, 121.95 and 128.21 mg/g. Electrostatic interaction, complexation, and precipitation caused by CaO in the forms of CaHPO₄ and Ca₅(PO₄)₃(OH) are responsible for the adsorption of phosphate using the biochars. The results of this study indicate that edible fungus residue can be developed as an inexpensive and efficient adsorption material for phosphorus removal.

Key words: edible fungi residue, Ca, biochar, phosphate, adsorption

摘要：

为了寻求食用菌菌渣合理的资源化利用途径和开发绿色、高效的除磷吸附剂，以香菇菌渣(mushroom residue， MR)为原料，将其在800、900和1000℃下碳化制备生物炭后用于含磷废水的处理(MR-800C、MR-900C和MR-1000C)。理化特性分析显示，该生物炭富含K、Na、Ca和Mg等矿物质，尤其是Ca，其含量高达4328.43~4919.38 mmol/kg。Ca在生物炭中主要以CaCO₃的形式存在，随着热解温度升高，部分被分解为CaO。另外，生物炭还具有较高的pH_pzc（11.86~12.04）、发达的孔隙结构(比表面积为167.56~223.80 m²/g)和丰富的表面官能团(如C\stackrel{}{̿}O、C\stackrel{}{̿}C、C—O、Ca—O等)。在磷的吸附过程中，生物炭对磷的吸附量服从MR-800C< MR-900C< MR-1000C，且均可被Langmuir吸附等温线模型和准二级动力学模型很好拟合，即该吸附过程为化学作用主导的单层吸附。MR-800C、MR-900C和MR-1000C对磷的理论最大吸附量分别为104.17、121.95和128.21 mg/g。静电作用、孔填塞、配位作用及CaO所引起的沉淀作用［形成CaHPO₄和Ca₅(PO₄)₃（OH）］在该过程中起着重要作用。结果表明，食用菌菌渣可被开发作为低廉、高效的除磷吸附材料。

关键词: 食用菌菌渣, Ca, 生物炭, 磷, 吸附