Universidade Federal de Minas Gerais, Research Group on Environmental Applications of Advanced Oxidation Processes, Av. Antônio Carlos 6627, 31270-901, Pampulha, Belo Horizonte, Brazil.
Universidade Federal de Minas Gerais, Research Group on Environmental Applications of Advanced Oxidation Processes, Av. Antônio Carlos 6627, 31270-901, Pampulha, Belo Horizonte, Brazil; Universidade Federal de Minas Gerais, Instituto de Ciências Biológicas, Departamento de Bioquímica e Imunologia, Pampulha, Belo Horizonte, MG, Brazil.
Sci Total Environ. 2021 Sep 10;786:147448. doi: 10.1016/j.scitotenv.2021.147448. Epub 2021 Apr 30.
This review aims to gather main achievements and limitations associated to the application of solar photocatalytic processes with regard to the removal of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) from municipal wastewater treatment plant effluent (MWWTPE). Solar photocatalytic processes were chosen considering the context of developing tropical countries. Among these processes, solar photo-Fenton has been proved effective for the elimination of ARB from MWWTPE at neutral pH in bench and pilot scale and also under continuous flow. Yet, ARG removal varies as according to the gene. Irradiation intensity and matrix composition play a key role on treatment efficiency for this purpose. The use of sulfate radical in modified solar photo-Fenton is still incipient for ARB and ARG removal. Also, investigations related to ARB resistance profile and horizontal gene transfer rates after solar photo-Fenton treatment must be further analyzed. Regarding solar heterogeneous photocatalysis, TiO and TiO-composites applied in suspension are the most commonly investigated for the removal of ARB and ARGs. Irradiation intensity, temperature and catalyst dosage affect treatment efficiency. However, most studies were performed in synthetic solutions using reduced sample volumes. Extended exposition times and addition of HO to the system (solar/TiO/HO) are required to prevent bacteria regrowth and ensure ARG abatement. In addition, enhancement of TiO with graphene or (semi)metals improved ARB elimination. Differences concerning irradiation intensity, matrix composition, catalyst dosage, and model ARB and ARGs used in studies analyzed in this review hinder the comparison of photocatalysts synthesized by various research groups. Finally, future research should aim at evaluating the efficiency of solar photocatalytic processes in real matrices originated from sewage treatment systems applied in developing countries; determining indicators of antimicrobial resistance in MWWTPE; and investigating ARB mutation rate as well as the removal of cell-free ARGs present in suspension in MWWTPE.
本综述旨在收集与应用太阳能光催化工艺去除城市污水处理厂出水（MWWTPE）中的抗生素耐药菌（ARB）和抗生素耐药基因（ARGs）相关的主要成果和局限性。鉴于发展中国家的背景，选择了这些工艺。在这些工艺中，太阳能光芬顿已被证明可有效去除 MWWTPE 中性 pH 值下的 ARB，且在 bench 和 pilot 规模以及连续流条件下均有效。然而，根据基因的不同，ARGs 的去除情况也有所不同。为此，辐照强度和基质组成对处理效率起着关键作用。在改性太阳能光芬顿中使用硫酸根自由基对于去除 ARB 和 ARG 仍处于初期阶段。此外，还必须进一步分析太阳能光芬顿处理后 ARB 耐药谱和水平基因转移率的相关研究。关于太阳能多相光催化，TiO 和 TiO 复合材料在悬浮液中的应用是最常用于去除 ARB 和 ARGs 的。辐照强度、温度和催化剂用量会影响处理效率。然而，大多数研究都是在使用减少的样品体积的合成溶液中进行的。需要延长暴露时间并向系统中添加 HO（太阳能/TiO/HO），以防止细菌再生并确保 ARG 减少。此外，通过在 TiO 中添加石墨烯或（半）金属可以提高 ARB 的去除率。本综述中分析的研究中，由于辐照强度、基质组成、催化剂用量以及所使用的模型 ARB 和 ARGs 的差异，阻碍了对不同研究小组合成的光催化剂的比较。最后，未来的研究应致力于评估太阳能光催化工艺在发展中国家应用的污水处理系统产生的实际基质中的效率；确定 MWWTPE 中抗微生物污染的指标；并研究 ARB 的突变率以及悬浮液中存在的无细胞 ARGs 的去除情况。
