Trong các hoạt động, chất rắn hấp phụ, thường là ở dạng hạt, được đưa tiếp xúc với hỗn hợp khí hoặc chất lỏng. Các chất rắn phải có khả năng ưu tiên tập trung hoặc hấp thụ trên bề mặt các thành phần cụ thể từ hỗn hợp. Hiện tượng này là có thể bởi vì các lực lượng hấp dẫn mà tồn tại giữa các nguyên tử, phân tử, và các ion giữ chất rắn lại với nhau đều không hài lòng ở bề mặt và do đó có sẵn để tổ chức các thành phần trong hỗn. | i Ọ Adsorption for HAP and VOC Control INTRODUCTION TO ADSORPTION OPERATIONS In adsorption operations solids usually in granular form are brought in contact with gaseous or liquid mixtures. The solids must have the ability to preferentially concentrate or adsorb on their surfaces specific components from the mixture. This phenomenon is possible because the attractive forces that exist between the atoms molecules and ions holding the solids together are unsatisfied at the surface and are thus available for holding the components in the mixtures to be adsorbed. Consequently these components can be separated from each other and the carrier fluid. Adsorption is used broadly in the chemical process industries. Early on one of its most significant applications was the drying of wet air over beds of solid desiccants for pneumatic control instruments. Original process applications range from solvent reclamation in dry cleaning to the recovery of ethyl acetate and toluene from cellophane drying operations. A broad area for adsorption application is in component recovery. Processes of this sort have been patented for fractionated petroleum products by oil and chemical companies. A typical early application was that of the Hypersorption process developed by the Union Oil Company of California in the mid-1940 s in which a moving bed of carbon separated light Another widespread application of adsorption is the recovery of valuable solvents from air streams. Of most relevance in this book are adsorption processes which are used to eliminate impurities from emissions to the ambient air. Solvent recovery removal of other organic compounds and odor removal are all important in producing clean effluents. The best applications of adsorption are in handling large volumes of air flow with dilute pollution levels and removal of the contaminants especially VOCs down to trace levels such as ppmv. Table summarizes some of these operations and the type of .
