反渗透工艺对污染物的去除率高，稳定性好，已被用于石化、冶金和电解锰等涉锰行业废水的处理和回用。然而，经过多级处理后，二级生化出水仍含有较高浓度的Mn²⁺，伴随有机物一同进入RO系统会引起膜污染。目前关于Mn²⁺对RO膜有机污染的影响缺乏全面系统的研究，污染机理尚未明确，控制机制仍不清楚，控制效果缺乏有效评价。因此，本研究以腐殖酸（HA）、海藻酸钠（SA）、牛血清蛋白（BSA）以及它们的混合物（HBS）代表二级生化出水中的腐殖酸类、多糖类和蛋白质类有机物以及有机混合物。研究Mn²⁺对不同类型有机物在RO膜上污染行为的影响规律，阐明作用机理；探究臭氧氧化和投加重金属捕集剂对Mn²⁺存在下的RO膜有机污染的控制效果与机制；提出一套基于获得更多出水总量为目标的全面可量化的前处理效果评估模型，用于前处理效果的优化调控。获得如下研究结论：

（1）只有50 mg/L HA、SA和HBS存在时，水通量分别下降4.7%、10.6%和21.7%，当Mn²⁺分别增至0.5 mM、0.05 mM和0.5 mM，通量开始显著下降。只有50 mg/L BSA存在时，水通量下降26.8%，膜污染显著，但随着Mn²⁺加入通量逐步恢复。膜污染与Mn²⁺无直接关系，和BSA浓度有关。Mn²⁺作用下RO膜污染程度为：HBS＞SA＞HA＞BSA，Mn²⁺对RO膜SA污染的作用强度显著高于HA，因此膜污染的防控可以优先考虑降低SA类污染物浓度。

（2）Mn²⁺与HA或SA或HBS共存下的RO膜污染主要是有机物上的羧基通过静电作用与Mn²⁺发生络合生成尺寸较大的络合物，络合作用降低了溶液的Zeta电位，促进络合物的聚集，进一步增大溶质粒径。同时，界面作用能下降促进了络合物在RO膜和污染层上的沉积。RO膜BSA污染不受Mn²⁺直接影响，Mn²⁺的加入引起了BSA的盐析效应，以单个分子形式析出沉积在膜上，同时粘附能抑制了BSA在膜上的沉积。污染速率的相关性分析得出，污染速率主要受Mn²⁺浓度、Zeta电位和总粘附能影响，减少进水中Mn²⁺浓度和膜改性是降低污染速率的有效的手段。

（3）臭氧可以将HA分子上的苯环破裂，减小溶质粒径，同时降低了总粘附能对膜污染的促进作用，一定程度上缓解了膜污染，在投加量分别为0.089 mg O₃/mg COD和0.18 mg O₃/mg COD 时，水通量恢复3.8%和6.4%；臭氧促进SA与Mn的络合，使粒径进一步变大，但降低了TEP浓度，减弱了粘附能对膜污染的促进作用，缓解了膜污染，在投加量分别为0.094 mg O₃/mg COD和0.16 mg O₃/mg COD 时，水通量恢复3.7%和5.0%；臭氧增强了HBS和Mn的络合作用，形成尺寸更大的HBS-Mn络合物，但增大了膜上污染层的孔隙，同时总粘附能和总粘聚能对膜污染的促进作用减弱，缓解了膜污染，在投加量分别为0.087 mg O₃/mg COD和0.17 mg O₃/mg COD时，水通量恢复3.2%和3.5%。

（4）投加重金属捕集剂可以将溶液中络合态Mn去除，破坏Mn²⁺的桥接作用，减弱污染物聚集程度，降低甚至抑制界面能对RO膜污染的促进作用，大大减轻膜污染。投加浓度为0.67 g/L时，由HA-Mn、SA-Mn和HBS-Mn引起的膜污染分别恢复17.4%、23.0%和22.9%，效果远高于臭氧氧化。

（5）前处理技术至少改善最终水通量或污染速率其中一个指标。标准化的出水总量（V_N）模型使前处理效果具有可比性，可用于前处理工艺选择和效果优化，具有较强的普适性。

Reverse osmosis technology, with its high pollutant removal rate and good stability, has been used in the treatment and reuse of manganese-affected industry wastewater, such as petrochemical, metallurgy, and electrolytic manganese. However, after multiple treatments, the effluent from the secondary biological treatment still contains a high concentration of Mn²⁺, which, together with organic matter, enters the RO system and causes membrane fouling. Currently, there was no comprehensive and systematic research about the impact of Mn²⁺ on RO membranes organic fouling. The fouling mechanism was still unclear, the control mechanism remained unknown, and the control effectiveness lacked convincing evaluation. Therefore, humic acid (HA), sodium alginate (SA), bovine serum albumin (BSA), and their mixtures (HBS) were used in this study to represent humic acids, polysaccharides, and proteins as well as organic mixtures in secondary biochemical effluent. To study the influence of Mn²⁺ on the contamination behavior of different types of organics on RO membranes, and to elucidate the mechanism of action; to investigate the control effect and mechanism of ozone oxidation and weighted metal trapping agent on the organic contamination of RO membranes in the presence of Mn²⁺; and to put forward a set of comprehensive and quantifiable pre-treatment effect assessment model based on the goal of obtaining more total amount of effluent for the optimization and regulation of the pretreatment effect. The following conclusions were obtained:

(1) Water flux decreased by 4.7%, 10.6%, and 21.7% in the presence of only 50 mg/L HA, SA, or HBS, respectively, and began to decrease significantly when Mn²⁺ was increased to 0.5 mM, 0.05 mM, and 0.5 mM, respectively. Only in the presence of 50 mg/L BSA, the water flux decreased by 26.8% with significant membrane contamination, but the flux gradually recovered with the addition of Mn²⁺. Membrane fouling has no direct relationship with Mn²⁺, and the BSA concentration was related. The degree of RO membrane fouling under the effect of Mn²⁺ was: HBS>SA>HA>BSA, and the effect of Mn²⁺ on RO membrane SA fouling was higher than that of HA, therefore, the control of membrane fouling should be prioritized to reduce the concentration of SA-type pollutants.

(2) In the presence of Mn²⁺ with HA SA or HBS, the RO membrane fouling was mainly due to the electrostatic complexation of the carboxyl groups on organic substances with Mn²⁺ to form larger complexes. The complexation reduced the solution's Zeta potential, promoting the complexes' aggregation and further increasing the solute particle size. At the same time, the decrease in interfacial interaction energy promoted the deposition of complexes on the RO membrane, exacerbating membrane fouling. RO membrane BSA fouling was not affected by Mn²⁺, possibly due to the salting-out effect caused by adding Mn²⁺, resulting in the deposition of BSA in a single molecular form on the membrane. At the same time, adhesion energy inhibited the deposition of BSA on the membrane, resulting in a milder membrane fouling. Fouling velocity was mainly affected by the concentration of Mn²⁺, Zeta potential, and total adhesion energy. Therefore, reducing the concentration of Mn²⁺ in the feed water and modifying the membrane were effective ways to reduce the fouling velocity.

(3) For HA，ozone oxidation broken the benzene ring on the HA molecule, reduced solute particle size, and simultaneously reduced the promoting effect of total adhesion energy on membrane fouling. This partially alleviated membrane fouling. Water flux recovers by 3.8% and 6.4% at dosages of 0.089 mg O₃/mg COD and 0.18 mg O₃/mg COD, respectively. For SA, ozone oxidation promoted the complexation between SA and Mn, further increasing the particle size, but reducing the concentration of TEP (transparent exopolymer particles) and weakening the promoting effect of adhesion energy on membrane fouling. This partially alleviated membrane fouling. Water flux recovers by 3.7% and 5.0% at dosages of 0.094 mg O₃/mg COD and 0.16 mg O₃/mg COD, respectively. For HBS, ozone oxidation enhanced the complexation between HBS and Mn, forming larger HBS-Mn complexes. However, it increased the porosity of the fouling layer on the membrane. At the same time, the promoting effect of total adhesion energy and total cohesion energy on membrane fouling weakened. This partially alleviates membrane fouling. Water flux recovers by 3.2% and 3.5% at dosages of 0.087 mg O₃/mg COD and 0.17 mg O₃/mg COD, respectively.

(4) The addition of heavy metal trapping agent can remove the complexed Mn in the solution, destroyed the bridging effect of Mn²⁺, weakened the degree of pollutant aggregation, reduced or even inhibited the promotional effect of interfacial energy on the RO membrane fouling, and greatly reduced the membrane fouling. When the concentration was 0.67 g/L, the membrane fouling caused by HA-Mn, SA-Mn, and HBS-Mn was restored by 17.4%, 23.0%, and 22.9%, respectively, which was much higher than that of ozone oxidation.

(5) Pretreatment technologies improved at least the final water flux or fouling velocity. Standardized total effluent (VN) models made pretreatment effects comparable and can be used for pretreatment process selection and effect optimization with high generalizability.