Hexavalent chromium (Cr(VI)) is one of the typical heavy metals that pose a great threat to the environment. As a novel biotechnology, algal-bacterial aerobic granular sludge (AGS) possesses the merits of both bacterial AGS and algae. This study firstly evaluated Cr(VI) removal via biosorption by algal-bacterial AGS under different operation conditions and then some environmental factors. Results show that the highest Cr(VI) reduction (99.3%) and total Cr removal (89.1%) were achieved within 6 h at pH 2 and 6, respectively. The coexisting oxyanions exhibited slight effects, while both tested natural organic matters (humic acid and tannic acid) and carbon sources promoted Cr(VI) reduction at some appropriate concentrations. The coexistence of metal cations favored Cr(VI) reduction, achieving the highest enhancement of 8.1% by Cu²⁺ at 5 mg/L, while the total Cr removal was suppressed to some extent. Salinity > 5 g/L severely inhibited both Cr(VI) reduction and total Cr removal. Moreover, the loaded Cr in algal-bacterial AGS was found to be almost in the form of Cr(III), with 66.8% being contributed by intracellular accumulation. This work suggests that Cr(VI) reduction and intracellular accumulation are the main mechanisms involved in Cr(IV) biosorption onto algal-bacterial AGS.

六价铬（Cr（VI））是对环境构成严重威胁的典型重金属之一。作为一种新型生物技术，藻类细菌需氧颗粒污泥（AGS）具有细菌AGS和藻类的优点。这项研究首先评估在不同的操作条件下通过藻类细菌AGS的生物吸附去除六价铬的行为，然后评估一些环境因素。结果表明，在6个工作日内，Cr（VI）的最高还原率（99.3％）和总Cr去除率（89.1％）达到了 h分别在pH 2和6。共存的氧阴离子显示出轻微的影响，而测试的天然有机物（腐殖酸和单宁酸）和碳源均以一定的浓度促进了Cr（VI）的还原。金属阳离子的共存有利于Cr（VI）的还原，Cu ²⁺在5  mg / L时实现最高的8.1％的增强，而总Cr的去除在一定程度上受到抑制。盐度> 5 g / L严重抑制了Cr（VI）的还原和总Cr的去除。此外，发现藻类细菌AGS中负载的Cr几乎以Cr（III）的形式存在，其中66.8％是由细胞内积累贡献的。这项工作表明Cr（VI）减少和细胞内积累是Cr（IV）生物吸附到藻类细菌AGS上的主要机制。