State Environmental Protection Key Laboratory of Environmental Pollution Health Risk Assessment, South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510655, China.
State Environmental Protection Key Laboratory of Environmental Pollution Health Risk Assessment, South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510655, China; Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou, 510006, China.
Sci Total Environ. 2023 Feb 1;858(Pt 2):159940. doi: 10.1016/j.scitotenv.2022.159940. Epub 2022 Nov 3.
In this study, the biochar-goethite composites (MBC@FH) were synthesized through co-ball milling and the degradation of triphenyl phosphate (TPhP) was compared in persulfate (PDS) alone system and MBC@FH&PDS systems. The results showed that TPhP can be effectively degraded in PDS alone system and degradation efficiency reached up to 90 % within reaction of 8 h, at a PDS concentration of 10 mM, a reaction temperature of 30 °C and a system pH of 6.12. The obvious degradation can be ascribed to the reactive oxygen species (ROS) generated by self-decompose of PDS, among which O, ∙OH and O∙ play a major role in the degradation process. Although 350 °C biochar-goethite composites (MBC35@FH) and 800 °C biochar-goethite composites (MBC80@FH) facilitated PDS activation to produce more ROS, the catalytic degradation of TPhP was different in their systems. The degradation of TPhP was inhibited by MBC35@FH due to its stronger adsorption for TPhP, while MBC80@FH promoted TPhP degradation and degradation efficiency was up to 100 % within 6 h. O and SO∙ played a stronger degradation role than ∙OH and O∙ in above systems. The transformation of Fe species, functional groups (oxygen-containing functional groups, pyrrolic nitrogen) and persistent free radicals (PFRs) on the MBC@FH were involved in the PDS activation to produce ROS. Furthermore, MBC80@FH was more capable of activating PDS than MBC35@FH due to its abundant defect sites, larger specific surface area, more PFRs, higher Fe content and stronger electron transfer capability. In addition, seven possible TPhP intermediates were identified and possible degradation pathways of TPhP were proposed accordingly. This study illustrated that not all metallic carbon catalysts are necessarily beneficial for organic contaminants degradation.
在这项研究中，通过共球磨合成了生物炭-针铁矿复合材料（MBC@FH），并比较了过硫酸盐（PDS）单独体系和 MBC@FH&PDS 体系中三苯基磷酸酯（TPhP）的降解情况。结果表明，TPhP 可以在 PDS 单独体系中有效降解，在 10mM 的 PDS 浓度、30°C 的反应温度和 6.12 的系统 pH 下，反应 8 小时后降解效率达到 90%。明显的降解归因于 PDS 自分解产生的活性氧物种（ROS），其中 O、∙OH 和 O∙在降解过程中起主要作用。尽管 350°C 生物炭-针铁矿复合材料（MBC35@FH）和 800°C 生物炭-针铁矿复合材料（MBC80@FH）促进了 PDS 的活化，产生了更多的 ROS，但它们体系中 TPhP 的催化降解情况却不同。由于 MBC35@FH 对 TPhP 的吸附更强，TPhP 的降解受到抑制，而 MBC80@FH 则促进了 TPhP 的降解，在 6 小时内降解效率达到 100%。在上述体系中，O 和 SO∙比 ∙OH 和 O∙具有更强的降解作用。MBC@FH 中 Fe 物种的转化、官能团（含氧官能团、吡咯氮）和持久自由基（PFRs）参与了 PDS 活化产生 ROS。此外，由于 MBC80@FH 具有丰富的缺陷位、更大的比表面积、更多的 PFRs、更高的 Fe 含量和更强的电子转移能力，因此比 MBC35@FH 更能激活 PDS。此外，鉴定了七种可能的 TPhP 中间体，并据此提出了 TPhP 的可能降解途径。本研究表明，并非所有金属碳催化剂都一定有利于有机污染物的降解。
