Synthesis Of Nanoporous Organic Absorbents And The Research On The Adsorption Performance Of Heavy Metal Ions

Nowadays, the problem of wastewater containing heavy metals has been become one of the biggest water pollution issues, which is mainly due to the arbitrary emmissions of industrial wastewater including electroplating, papermaking, mining and the unreasonable application of pesticides and fertilizers, together with the domestic sewage. With bioaccumulation effect, heavy metal ions finally can be taken into human body through the food chain and accumulate in human body, then damage the organs and tissues, which seriously endangers human health. Thus, the question of developing environmental-friendly, economical and efficient methods to remove heavy metals from wastewater has become the overarching focus for many researchers around the world.In recent years, many methods used to remove heavy metal ions from wastewater have been reported, such as chemical precipitation, membrane separation, ion exchange, electrochemical, biomass, flocculation and adsorption, etc. All of these methods play certain effects towards removing heavy metal ions from wastewater. However, there exits inferiority, such as the high cost, easy to cause secondary pollution, complicated preparation method or poor selectivity, etc. Yet, adsorption method has attracted much attention owning to its extensive material sources, simple processing equipment, high adsorption efficiency, fast adsorption, easy to recycle, and other advantages.In this paper, two new nanoporous absorbents about organic bisulfide PTCY and PTMT were successfully prepared from Na3C3N3S3 (TMT15) which is a commonly used homogeneous aqueous solution absorbent in the industry. These solid phase adsorbing materials not only retained the advantages of TMT15 homogeneous absorbent about high adsorption quantity, high adsorption efficiency, fast adsorption, environmental-friendly and non-secondary pollution, but also avoided the recycle deficiencies of TMT15 as the homogeneous absorbent.Nitrogen adsorption isotherms, IR and Raman spectra, solid nuclear magnetic and other characterization methods were used to prove the existence of mesoporous structure in the two kinds of as-synthesized absorbents which played an important role in the removal of metal ions. Meanwhile, the adsorption performance of PTCY towards Pb2+ and Cd2+, as well as PTMT towards Pb2+ and Hg2+ were studied carefully. By comparing the results, we found that the introduction of thiol into PTMT not only improving the adsorption selectivity, but also upgrading the adsorption capacity greatly, especially for Pb2+ and Hg2+ with high adsorption capacities about 375.9 and 735.3 mg/g, respectively, which were much higher than many other reported adsorbing materials. Besides, the kinetics and adsorption isotherms were also carefully studied. The experimental results showed that the two adsorbing materials were consistent with the secondary kinetic process and Langmuir monolayer adsorption model. Moreover, the adsorption experiments of Hg2+ by PTMT can be recycled 4 times with less decreased adsorption efficiency.The above-mentioned results indicate that the adsorbing materials prepared by simple reaction of TMT15 in aqueous solution, especially for PTMT, not only have a simple preparation process, but also show the excellent adsorption performance and satisfactory cycling life. Therefore, they will have a very broad market application prospect in heavy metal wastewater treatment industry. In short, they will not only extend the application of the TMT15 derivatives in wastewater treatment industry, but also provide a new way to the design and preparation of new adsorbing materials.