Heterogeneous catalysis water treatment

Generally, the above transesterification reactions are catalyzed by strong acids or alkalis [1, 2]. In the homogeneous catalytic process by acids or alkalis, neutralization is required of the product. This post-treatment produces waste water, and increases equipment investment and production cost. Recently, more attention has been paid to the heterogeneous catalysis process [3] for an easier production process and to reduce pollution of the environment. 

Why adsorption, ion exchange and heterogeneous catalysis in one book The basic similarity between these phenomena is that they all are heterogeneous fluid-solid operations. Second, they are all driven by diffusion in the solid phase. Thus, mass transfer and solid-phase diffusion, rate-limiting steps, and other related phenomena are common. Third, the many aspects of the operations design of some reactors are essentially the same or at least similar, for example, the hydraulic analysis and scale-up. Furthermore, they all have important environmental applications, and more specifically they are all applied in gas and/or water treatment. 

Ibusuki T, Kutsuna S, Takeuchi K, Shin-Kai K, Samamato T, Miyamato M. Removal of low concentration air pollutants through photoassisted heterogeneous catalysis. In Ollis DF, Al-Ekabi H, eds. Photocatalytic Purification and Treatment of Water and Air. Amsterdam Elsevier, 1993 375-386. 

The term reactive filtration may be used in a variety of applications. A simple search of the internet provides results such as reactive filter paper [1], adsorption filters for removing heavy metals from water [2], solid matrices used in organic synthesis [3], membranes for wastewater treatment, or even dialysis machines, filters for deep-frying pans and devices for the dechlorination of shower water by reaction with vitamin C. Most of the applications termed reactive filtration would be named heterogeneous catalysis or adsorption from a chemical engineer s point of view. 

Ibiisiiki, T., Kiitsiina, S., and Takeiichi, K., 1993, Removal of low concentration air pollutants through pho-toassisted heterogeneous catalysis, in Photocatalytic purification and treatment of water and air, Ollis, D., and Al-ekabi, H., eds., Elsevier, pp 37.5-386. 

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