Chlorine Adsorption Properties Of Activated Carbons, Carbon Molecular Sieves And Carbon Nanotubes

Chlorine has extremely extensive application in industrial and agricultural production, scientific research and human daily life, and has been created huge social wealth in the last 100 years. Chlorine is widely used in preparation of acid, pesticide, explosives and organic dyes, synthesizing rubber and plastic, bleaching paper, disinfecting textiles and drinking water, also treating industrial wastewater. With the increasing of chlorine dosage, the production of the exhaust containing chlorine is also more and more. The chlorine contained gas will endanger on human health and the growth of plants and animals if they are exhaust directly. Then chlorine-gases handling also become a very serious problem in industrial production.At present, most of the factories use alkali liquor, water, or organic solvent to absorb tail-gases, or burn it to produce Hydrochloric Acid. All of the above methods are high cost and producing secondary pollution to environment. Now adopt solid adsorbents by pressure swing adsorption (PSA) recycling chlorine become the research focus and widely used in mixture gases separation fields, with many advantages as following: low cost, high efficiency, low energy consumption and high degree of automation. But there still exist some problems when recovering chlorine, mainly embodies in poor selectivity, worse corrosion resistance, and short service life of the adsorbents. Then carbon materials are chosen with good adsorption performance and stability of chemical properties, better corrosion resistance of strong alkali and acid, can endure water, high temperature and high pressure as adsorbents treating chlorine to study.In this paper, research progresses of chlorine absorption properties were summarized. The P-C-T chlorine absorption apparatus was adopted to study chlorine absorption properties of activated carbon (ACs), carbon molecular sieves (CMSs) and carbon nanotubes (CNTs). The stability of the samples was characterized by FTIR spectrum and XRD diffraction.Main conclusions obtained as follows:1 At 0℃,30℃and 50℃, the chlorine absorption curves of all samples accorded with Langmuir equation and the adsorption belonged to physical process. Chlorine absorption amount increased with the temperature decreased and pressure increased.2 At 30℃, the chlorine adsorption capacity were hardly changed after adsorbed repeatedly for many times, combining with XRD diffraction, we ascertained that carbon materials can be used treating chlorine.3 Experimental data showed that pore volume and pore diameter of samples influenced chlorine adsorption capacity. The pore volume and pore diameter of CNTs was larger than that of ACs and CMSs, then the chlorine adsorption capacity of CNTs was the largest one. CMSs with the smallest pore volume and pore diameter then had minimum chlorine adsorption capacity. At 30℃and 0.332MPa, the chlorine adsorption capacity of CNTs is 37.51%, but that of ACs and CMSs is 31.95% and 29.24% respectively.4 The FTIR spectrum showed that, after chlorine absorption the characteristic peaks of the skeleton structure of of ACs, CMSs and CNTs the samples were also existed. XRD spectrum showed that the diffractions of all samples were still in, but peaks intensity was slightly weakened. All of those indicated that after adsorption chlorine didn't destroy graphite microcrystalline structure and carbon amorphous structure of samples.