Hybrid System of Adsorption and Membrane Separation

介绍了粉末活性炭（SAC）在超滤（UF）过程中吸附去除合成有机化合物（SOC）的几种应用前景，并对其去除机理进行了探讨。该模型在未做任何修改的情况下，成功地应用于终端模式和跨流模式操作，验证了内部扩散控制机制的假设和连续搅拌罐式反应器（CSTR）概念。即使当OF以交叉流模式运行时，添加的PAC也只能在很短的时间内悬浮再循环。溶质的吸收主要是通过固定在膜管中的PAC进行的，不仅适用于死端操作，也适用于跨流操作。因此，在PAC上的SOC传质方面，交叉流操作与死角操作相比没有任何优势。模型模拟表明，在过滤循环开始时脉冲添加PAC比连续添加PAC去除SOC效果更好。然而，对于脉冲PAC添加模式，该模型预测的出水有机碳浓度略低于实测值，并且脉冲PAC应用在降低有机碳方面的效益优于其连续投加量尚未得到证实。脉冲给药时PAC的保持时间较长，可能会进一步降低内部扩散系数

This study describes several application potentials with a recently developed model for predicting the synthetic organic chemical (SOC) removal by powdered activated carbon (SAC) adsorption during ultrafiltration (UF) and discusses the removal mechanism. The model was successfully applied, without any modification, to dead-end mode operation as well as to cross-flow mode operation, validating the assumption of the internal diffusion control mechanism and the continuously-stirred-tank-reactor (CSTR) concept. Even when OF was operated in a cross-flow mode, PAC added was re-circulating in suspension for only a short time. Then, solute uptake took place mostly by PAC immobilized in membrane tubes not only for dead-end operation but also for cross-flow operation. Therefore, cross-flow operation did not have any advantage regarding the SOC mass transfer on PAC in OF loop over dead-end operation. The model simulation implied that pulse PAC addition at the beginning of filtration cycle resulted better SOC removal than continuous PAC addition. However, for the pulse PAC addition mode, the model predicted somewhat lower effluent SOC concentration than the observed values, and the benefit of pulse PAC application in terms of reducing SOC over its continuous dosage was not confirmed. Longer retention tune of PAC dosed in a pulse than continuously dosed PAC could possibly further decrease internal diffusivity