研究报告
宋亚丽,赵健淇,朱文芳,薛向东,郑磊,俞娅,汪华.老化前后聚苯乙烯微塑料对天然有机物的吸附[J].环境科学学报,2023,43(2):181-191
老化前后聚苯乙烯微塑料对天然有机物的吸附
- Adsorption of natural organic matter on original and aged polystyrene microplastics
- 基金项目：浙江省自然科学基金项目（No.LY16E080007）；浙江科技学院研究生教学改革研究项目（No.2021yjsjg02）；浙江科技学院院基本科研业务费专项（No.2021QN003）
- 作者
- 单位
- 宋亚丽
- 浙江科技学院土木与建筑工程学院，杭州310023;浙江科技学院浙江省废弃生物质循环利用与生态处理技术重点实验室，杭州310023
- 赵健淇
- 浙江科技学院土木与建筑工程学院，杭州310023
- 朱文芳
- 浙江科技学院土木与建筑工程学院，杭州310023;浙江科技学院浙江省废弃生物质循环利用与生态处理技术重点实验室，杭州310023
- 薛向东
- 浙江科技学院土木与建筑工程学院，杭州310023;浙江科技学院浙江省废弃生物质循环利用与生态处理技术重点实验室，杭州310023
- 郑磊
- 浙江科技学院土木与建筑工程学院，杭州310023;浙江科技学院浙江省废弃生物质循环利用与生态处理技术重点实验室，杭州310023
- 俞娅
- 浙江科技学院土木与建筑工程学院，杭州310023
- 汪华
- 浙江科技学院土木与建筑工程学院，杭州310023;浙江科技学院浙江省废弃生物质循环利用与生态处理技术重点实验室，杭州310023
- 摘要：随着地表水环境中微塑料的不断检出，微塑料污染受到广泛关注.微塑料是一类比表面积较大的疏水性物质，具有一定的吸附作用，其势必对地表水中的天然有机物产生影响.此外，暴露于自然环境下的微塑料也会受到紫外辐射或氧化等过程的影响，从而改变其物理化学性质，影响其对天然有机物的作用.本文开展了聚苯乙烯微塑料（mPS）经紫外和过氧化氢老化前后吸附腐殖酸（HA）和富里酸（FA）的对比研究.结果表明，老化过程使微塑料的孔隙和表面粗糙度明显增加，比表面积有大幅提高，但结晶度减小，官能团没有明显变化.疏水性的mPS微塑料对HA的吸附效果好于FA，且老化微塑料对两种有机物的吸附能力皆高于老化前，微塑料的吸附能力与比表面积大小呈正相关关系.吸附试验数据皆较好地拟合了准二级动力学模型（R2>0.93）和Freundlich模型（R2>0.91），微塑料对HA和FA的吸附以多层不均匀的物理吸附为主，两者在微塑料上的吸附分别为自发的放热和吸热反应过程.试验微塑料对HA和FA的吸附能力皆随着pH的增加呈先降低后增加的趋势.两种有机物在超纯水和地表水介质中的解吸率具有相似的趋势，即在地表水中的解吸率皆较超纯水中低，且老化微塑料皆获得较低的解吸率.HA和FA在试验微塑料上的吸附主要以疏水作用和n-π、π-π相互作用为主.
- Abstract：Microplastics （MPs） in surface water are gaining concerns due to the frequent detections. MPs have good adsorption capacity， as its hydrophobic property with large surface area， and thus will take effect to natural organic matter in surface water. In addition， through UV radiation or photo-oxidation in the natural environment， the physical and chemical properties of MPs and their adsorption capability of natural organic matter will be changed. Thus， this study took polystyrene MPs （mPS） as model MPs， to investigate UV and hydrogen peroxide aging influences on MPs adsorption of humic acid （HA） and fulvic acid （FA）. The results indicated that aging processes significantly increased the porosity， roughness， and specific surface area of mPS， and decreased the crystallinity， while functional groups were almost remained. Compared to FA， mPS had a larger adsorption capacity to HA， either original or aged ones. However， aging processes remarkably improved the adsorption ability which is positively correlated with specific surface area of the mPS. The adsorption kinetics and isotherm of HA and FA on the original and the aged mPS all well fitted the Pseudo-second-order model （R2>0.93） and Freundlich model （R2>0.91）， respectively， suggesting that the adsorption was multi-layer heterogeneous physical process， and the adsorption of HA and FA were spontaneous exothermic and endothermic， respectively. The adsorption capacity of mPS for HA and FA decreased first and then increased with the increase of pH. The desorption efficiencies of the two organic compounds in ultrapure water and surface water showed similar trends： the desorption efficiencies in surface water were lower than those in ultrapure water， and aged mPS released less. Hydrophobic， n-π and π-π interactions played main roles on HA and FA adsorption on mPS.
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