Biosorption of cadmium in solution by viable bacteria immobilized on biochar was tested under culture conditions, and the relative importance of biosorption by bacterial cell and biochar matrix was investigated. Viable Bacillus cereus RC-1 was immobilized on the biochars derived from rice straw (RSB-beads), chicken manure (CMB-beads), and sewage sludge (SSB-beads), respectively. The biosorption characteristics of immobilized beads was investigated under variable pH, incubation time, and initial Cd²⁺ concentration. The best results were obtained with RSB-beads that adsorbed Cd²⁺ of 158.77 mg/g, and the biosorption by these immobilized cells was superior when compared to cells in suspension. High biosorption capacity was the result of simultaneous adsorption resulting from biochar and bacteria, and accumulation resulting from bacteria, in which the bacterial cells contributed more than the abiotic biochar matrix to total removal, but only when initial Cd²⁺ concentrations were less than180 mg/L. The biochars played a dual role of adsorbent and carrier, and was struggling to provide nutrients to the bacteria. The relative contribution of each mechanism was determined, which demonstrated that ion-exchange was predominant in RSB-beads (contributing 39.5%-45.7% depending on initial Cd²⁺ concentration) and in CMB-beads (41.4%-46.8%). In contrast, ion-exchange was a minor fraction for SSB-beads (15.6%-20.1%), where complexation was the most important component (56.9%-66.8%). We propose a model regarding the roles of different mechanisms, which may provide insights into the biosorption process by microorganism immobilized onto a biochar matrix for heavy metal removal, as an important step towards improving microbial remediation.

在培养条件下测试了固定在生物炭上的活菌对溶液中镉的生物吸附，并研究了细菌细胞和生物炭基质对镉的相对重要性。可行的蜡状芽孢杆菌RC-1固定在从稻草（RSB-珠），鸡粪（CMB-珠），和污水污泥（SSB-珠），分别获得的生物炭。在可变的pH，孵育时间和初始Cd ²⁺浓度下研究了固定化珠的生物吸附特性。吸附Cd ^2+的RSB磁珠获得了最佳结果158.77 mg / g，并且与悬浮细胞相比，这些固定化细胞的生物吸附性更高。高生物吸附能力是生物炭和细菌同时吸附以及细菌积累的结果，其中细菌细胞对总去除的贡献超过非生物生物炭基质，但仅当初始Cd ²⁺浓度小于180 mg / L. 生物炭起着吸附剂和载体的双重作用，并努力为细菌提供营养。确定了每种机制的相对贡献，这表明离子交换在RSB-磁珠中占主导地位（贡献39.5％-45.7％，取决于初始Cd ²⁺浓度）和CMB珠（41.4％-46.8％）中。相比之下，离子交换对于SSB磁珠来说是次要的部分（15.6％-20.1％），其中络合是最重要的组成部分（56.9％-66.8％）。我们提出了一个有关不同机制作用的模型，该模型可为固定化到用于重金属去除的生物炭基质上的微生物提供微生物吸附过程的见解，作为改善微生物修复的重要步骤。