基于超声波原位增渗的地下水中苯酚污染的高效降解

Efficient degradation of phenol contamination in groundwater based on in-situ infiltration enhancement with ultrasound treatment

近年来,石油类有机污染物引起的地下水污染状况日趋严重,在传统原位化学氧化修复技术中,药剂的迁移扩散受含水层渗透性及非均质性的影响显著,寻求行之有效的原位增渗方法是提高修复药剂影响半径以及污染物修复效率的关键所在。超声波增渗技术具有对环境扰动小、无二次污染及装置简单易安装等优势,被广泛应用于改善煤岩和油层渗透率等领域,以此提高煤气和石油采收率。然而将超声波作为增渗技术应用于地下水原位修复领域的报道甚少,增渗效果和修复机理仍然有待深入研究。通过对两种不同的含水介质施加超声波作用,对比分析超声前后介质中孔径及孔隙连通性的变化、高锰酸钾的运移速率以及苯酚的降解效率,阐明超声波原位增渗的作用机理和影响因素,并探讨基于超声原位增渗下有机污染物的降解动力学。结果表明,影响超声波原位增渗效果及有机物污染物降解效率的主要因素有超声作用功率、介质粒径、超声波作用模式以及地下水流速等。超声波原位增渗效果会随着超声作用功率和介质粒径的增大而增强,通过对介质施加500 W的超声波作用150 min,可最大程度地提升高锰酸钾的运移速率达3.02倍;此外,当地下水流速为8.59 cm·d^(-1)时,超声波预处理作用方式可最大程度将苯酚降解率从78.61%提升至91.45%。本研究通过探索超声波原位增渗对修复药剂传输速率以及污染物修复效率的作用机理,可为开拓地下水原位修复技术的应用前景提供可靠的理论依据和技术支持。

In recent years,the situation of groundwater pollution caused by petroleum organic pollutants has become increasingly serious.In the traditional in situ chemical oxidation remediation technology,the migration and diffusion of chemicals are significantly affected by the permeability and heterogeneity of aquifers.The key to improve the influence radius of remediation agents and the efficiency of pollutant remediation is to find an effective in situ infiltration method.Ultrasound enhanced permeability technology has the advantages of small disturbance to the environment,no secondary pollution and simple installation of the device.Ultrasound technology is widely used in areas such as improving permeability of coal rocks and oil seams as a way to enhance gas and oil recovery.However,there are few reports on the application of ultrasound in groundwater insitu remediation,and the effect of infiltration enhancement and remediation mechanism still need to be studied in depth.Therefore,by applying ultrasound treatment to two different aqueous media,comparative analysis of changes in pore size and pore connectivity,potassium permanganate transmission rate,and phenol degradation efficiency in media before and after sonication.To elucidate the mechanism of action and influencing factors of ultrasound in-situ infiltration enhancement,and to explore the degradation kinetics of organic pollutants based on ultrasound in-situ infiltration enhancement.The results showed that the main factors affecting the effect of ultrasound in-situ infiltration enhancement and the degradation efficiency of organic pollutants were ultrasound action power,media particle size,ultrasound mode of action and groundwater velocity.The effect of ultrasound in-situ infiltration enhancement increased with the increase of ultrasound power and media particle size.By applying 500 W ultrasound treatment to the medium for 150 min,the transmission rate of potassium permanganate can be maximized up to 3.02 times.In addition,when the groundwater velocity was 8.59 cm·d^(−1),ultrasound pretreatment mode of action can maximize the phenol remediation efficiency from 78.61%to 91.45%.This study explored the mechanism of ultrasonic in-situ infiltration enhancement on the transfer rate of remediation chemicals and the efficiency of pollutant remediation.It can provide reliable theoretical basis and technical support for developing the application prospect of in-situ groundwater remediation technology.