乙草胺除草剂在我国农业生产中使用量较大，它在自然环境中性质稳定，难挥发，不易光解，能多介质迁移，因而在各类水体环境中被检出。同时，乙草胺具有内分泌干扰作用和遗传毒性。因此研发有效去除乙草胺污染物的方法对保护生态环境安全和人体健康具有重要意义。本文研发了一种“吸附+热活化过硫酸盐氧化”联合法，用于水体环境中的乙草胺污染物的高效去除，即以传统的活性炭材料为吸附剂，研究其对乙草胺污染物的吸附性能和机理，并创新地采用热活化过硫酸盐高级氧化法对吸附乙草胺的活性炭吸附剂进行再生利用，分析了吸附剂表面乙草胺的降解效能，评价了活性炭材料的再生性能和热活化过硫酸盐氧化法再生吸附剂的可行性。主要研究内容和结果如下：

  （1）首先研究了颗粒活性炭（GAC）和柱状颗粒活性炭（C-GAC）对乙草胺的吸附性能和机理。主要考察了吸附剂用量、乙草胺初始浓度、pH、离子强度和腐殖质等因素对乙草胺吸附的影响。结果表明水体pH、离子强度和HA等对乙草胺吸附没有明显影响。GAC和C-GAC对乙草胺的吸附分别符合伪一阶和伪二阶动力学模型。而GAC和C-GAC对乙草胺的吸附等温线符合Freundlich模型，说明GAC和C-GAC对乙草胺是不均一的多分子层吸附。最后，采用活化过硫酸盐氧化法对吸附后的GAC和C-GAC进行再生利用，发现Fe²⁺活化PDS氧化法并不能够有效降解GAC表面吸附的乙草胺污染物。而在70 ^oC再生温度下，当PDS投加量为80 mM，再生时间为10 h时，GAC表面的乙草胺的降解效率约为83%，GAC的再生效率在5次吸附-再生循环后保持在80%以上；当PDS投加量为160 mM，再生时间为8 h时，C-GAC表面的乙草胺的降解效率约为60.6%，C-GAC的再生效率在前3次吸附-再生实验中均在55%以上。总之，热活化PDS氧化法能够同时实现乙草胺污染物的降解和颗粒活性炭的再生。

    （2）进一步采用高温水热法合成活性炭负载铁酸锰磁性吸附材料（MnFe₂O₄@AC），并用于水体中乙草胺的吸附去除。采用SEM、TEM、FTIR、XRD、BET、TGA和VSM等技术对MnFe₂O₄@AC进行表征分析，发现MnFe₂O₄@AC具有良好的磁性，易于从水体中磁性分离。探讨了MnFe₂O₄/AC负载比例、吸附剂用量、乙草胺初始浓度、pH、离子强度、HA和共存重金属等因素对乙草胺吸附的影响。发现pH、离子强度和HA等水环境因素对MnFe₂O₄@AC吸附乙草胺没有产生明显影响，这有利于MnFe₂O₄@AC在实际水体中的应用；共存的重金属离子Cd(Ⅱ)和Cu(Ⅱ)没有明显影响MnFe₂O₄@AC对乙草胺吸附，而高浓度（5-10 mg L^-1）的Cr(Ⅵ)则会抑制乙草胺的吸附。MnFe₂O₄@AC对乙草胺的吸附符合伪二阶动力学模型（R²>0.99），化学吸附占主导地位，而颗粒扩散模型说明薄膜扩散和颗粒内部扩散共同控制乙草胺的吸附速率。Langmuir模型更能描述乙草胺在MnFe₂O₄@AC吸附剂上的等温吸附，说明发生了均一的单分子层吸附，乙草胺最大吸附量为226.76 mg g^-1。吸附热力学实验结果表明乙草胺的吸附是自发的放热过程。MnFe₂O₄@AC对乙草胺的吸附机理主要包括孔隙填充、氢键作用和π-π作用。采用热活化PMS氧化法再生MnFe₂O₄@AC吸附剂，并探究了PMS浓度、再生时间和再生温度对表面乙草胺降解和吸附剂再生效率的影响。当反应温度为70 ^oC，PMS浓度为9.6 mM，反应时间为12 h时，乙草胺的降解效率约为93%。XPS表征结果证明MnFe₂O₄在热辅助下发挥了催化剂作用，提高了反应速率和吸附剂表面乙草胺的降解效率。然后，进一步评价了MnFe₂O₄@AC的再生效率，发现和GAC不同，在3个吸附-再生循环实验后，MnFe₂O₄@AC的再生效率不足30%，这可能是因为MnFe₂O₄@AC的表面结构功能被破坏以及大量乙草胺降解产物残留在吸附剂表面。

总之，本文提出了一种经济高效和环境友好的“吸附+热活化过硫酸盐氧化”联合法,可用于吸附和降解不同水体环境中的乙草胺，并同时实现吸附剂的再生利用, 该方法可广泛用于水环境修复领域。本文的研究成果可以为水体中乙草胺以及其它有机污染物的去除提供一定的借鉴价值和理论支持。

Acetochlor is one of the most important chloroacetamide herbicides in China, with a frequent detection in various environmental media due to its characteristics of wide application, stable property, low volatility and multimedia migration. It has been reported that acetochlor is an endocrine interfering substance with inherent toxicity. Therefore, it is crucial to seek reliable and efficient methods to remove acetochlor herbicide from the contaminated environment, which is of great importance to protect ecological environment security and human health. In this study, adsorption combined with heat-activated persulfate oxidation process was provided to effectively remove acetochlor from the aquatic environment. Activated carbon adsorbents were used for acetochlor adsorption from aqueous solution. Adsorption performances and mechanisms for acetochlor were investigated in detail, respectively. After adsorption, the spent adsorbents were regenerated using heat-activated persulfate oxidation process with degrading the adsorbed acetochlor simultaneously and the reusability of adsorbents was evaluated by conducting adsorption-regeneration cycle experiments. The main contents and results of this research are as follows:

(1) GAC and C-GAC were used for acetochlor adsorption. The effects of adsorbent dosage, initial acetochlor concentration, pH, ionic strength and HA on acetochlor adsorption were studied. It was found that solution chemistry including pH, ionic strength and HA have insignificant effect on acetochlor adsorption onto GAC. The results indicated that adsorption kinetics data of GAC and C-GAC were well fitted with pseudo-first-order model and pseudo-second-order model, respectively. Adsorption isotherms data are well described by Freundlich isotherm model, suggesting that acetochlor adsorption onto GAC and C-GAC was heterogenous and multilayer adsorption process. Finally, the regeneration experiments found that the adsorbed acetochlor on GAC was hardly degraded in Fe²⁺-activated PDS oxidation process, but the degradation efficiency of adsorbed acetochlor was about 83% when the reaction conditions was 70 ^oC of temperature, 80 mM of PDS and 10 h of reaction time, in which GAC regeneration efficiency was above 80% after five adsorption-regeneration cycle experiments, while 60.6% of the adsorbed acetochlor on C-GAC was degraded and C-GAC regeneration efficiency was higher than 55% in the first three adsorption-regeneration cycle experiments in the condition of 70 ^oC of temperature, 160 mM of PDS and 8 h of reaction time. The above results indicated that heat-activated PDS oxidation could not only degrade the adsorbed acetochlor pollutants, but regenerate the spent GAC.

(2) MnFe₂O₄ supported activated carbon magnetic adsorbent (MnFe₂O₄@AC) was successfully synthesized via a simple one-pot solvothermal method and used for acetochlor adsorption from aqueous solution. Several parameters affecting acetochlor adsorption including MnFe₂O₄ /AC mass ratios, adsorbent dosage, initial acetochlor concentration, pH, ionic strength, humic acid (HA) and heavy metal ions were studied in detail. The adsorption kinetics data were well described by pseudo-second-order model（R²>0.99）. For adsorption isotherms study, the data were fitted well with Langmuir isotherm model with the maximum adsorption capacity of 226.76 mg g^-1 at 298 K. Thermodynamic studies indicated that acetochlor adsorption is a spontaneous and exothermic process. Besides, adsorption mechanisms of acetochlor can be attributed to the pore-filling effect, hydrogen bonding and π-π interaction. Eventually, the spent MnFe₂O₄@AC was regenerated through heat-activated PMS oxidation and the results implied that about 93% of the adsorbed acetochlor could be degraded efficiently at 70 ^oC when the PMS concentration and reaction time were 9.6 mM and 12 h, respectively. However, the regeneration efficiency of spent MnFe₂O₄@AC was below 30% after three adsorption-regeneration successive experiments, which was attributed to the damage of adsorbent structure and the accumulation of acetochlor degradation intermediates. Meanwhile, the regeneration process confirmed that MnFe₂O₄ nanoparticles acted as a catalyst to accelerate the activation of PMS with the assistance of heat for the efficient degradation of adsorbed acetochlor based on XPS analysis results.

        In conclusion, this study proposed a cost-effective, efficient and environment-friendly approach of adsorption combined heat-activated PMS oxidation process, which could be applied for the adsorption and degradation of acetochlor pesticides in different water matrix, and could simultaneously achieve the regeneration and reuse of the spent adsorbent. Additionally, this strategy shows a great application potential in wastewater treatment. The investigation results can also provide technical support and theoretical guidance for organic pollutants removal from aquatic environment.