Ultrafiltration(UF)membrane fouling by organic matter remains a significant challenge in the application of low pressure membrane filtration in the seawater desalination project. Powdered activated carbon(PAC)adsorption is one of the most common pretreatment technologies for seawater ultrafiltration process. In this paper,removal of organic matter from seawater using UF and PAC-UF processes were compared. The influence of PAC addition on organic matter removal was investigated using excitation-emission matrix(EEM) spectroscopy. Flux decline and membrane fouling in seawater ultrafiltration processes with and without PAC addition were also discussed. The experimental results indicated that PAC addition increased turbidity and organic matter removal from seawater. DOC removal by UF increased from 55.1% without PAC to 77.6% when 200mg/L PAC was added. The higher humic acid(HA)substances removal rate by PAC-UF processes can be attribute to PAC adsorption and cake formation on the membrane surface. It was not significantly to decrease the flux decline rate after PAC adding in comparison to ultrafiltration without PAC addition. However,the cake formation on the membrane surface can avoid organic matter contacting directly with the membrane, which is helpful to mitigate irreversible membrane fouling.%超滤膜的有机污染问题是膜法海水预处理技术在海水淡化工程应用面临的重要挑战，粉末活性炭吸附是目前常用的膜前预处理手段之一。本文对比分析了直接超滤和投加粉末活性炭后对海水中有机物的截留能力，利用三维荧光光谱分析了投加粉末活性炭对超滤膜截留有机物的影响机制，并考察了海水超滤过程中通量变化及膜污染情况。研究结果表明，投加粉末活性炭能够强化超滤膜对海水浊度和有机物的去除，当粉末活性炭投量为200mg/L时，整个系统对海水中DOC去除率从直接超滤时的55.1%提高到77.6%。利用粉末活性炭的吸附作用及其在超滤膜表面形成的疏松滤饼层能够显著提高超滤系统对海水中腐植酸类有机物的去除能力。与直接超滤相比，粉末活性炭-超滤系统对改善膜通量的作用有限，但粉末活性炭形成的滤饼层能够避免超滤膜与有机物直接接触，可显著减缓超滤膜的不可逆污染。
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