Synthesis Of Sulphydryl Silane-modified Multiwall Carbon Nanotubes And Its Adsorption Capacity To Cadmium And Lead

In this study,sulphydryl multi-walled carbon nanotubes were prepared by using multi-walled carbon nanotubes and silane coupling agent 3-mercaptopropyltrimethoxysilane(MPTMS)as raw materials and applied by mass adsorption Heavy metal ions cadmium and lead removal,the influencing factors affecting the removal of heavy metals and the adsorption mechanism were studied,and the following research results and conclusions were obtained:1.Preparation of sulphydryl multi-walled carbon nanotubes(SH-MWCNTs)by modification of MWCNTs with 3-mercaptopropyltrimethoxysilane(MPTMS)as silane coupling agent.SH-MWCNTs were characterized by scanning electron microscopy(SEM),X-ray photon energy meter(EDS)and infrared spectroscopy(FT-IR).The SEM,EDS and FT-IR results showed that MPTMS had successfully grafted onto MWCNTs,and SH-MWCNTs were successfully prepared.2.The effects of initial pH,adsorbent dosage,adsorption time and initial Cd2+ concentration on the adsorption effect were studied by the adsorption of cadmium in water by sulphydryl multi-walled carbon nanotubes(SH-MWCNTs)The adsorption kinetics and adsorption isotherm characteristics were analyzed.The results showed that the adsorption time was 90 min and the pH was 4,the adsorption capacity was the best,and the adsorption capacity increased with the increase of SH-MWCNTs and the concentration of Cd2+.The adsorption kinetics and adsorption isotherm study showed that,the adsorption kinetics coincides with the quasi-second order linear equation.The adsorption isotherm is in accordance with the Freundlich and Langmuir models.Adsorption is mainly composed of monomolecular adsorption and multilayer adsorption.3.The effects of initial pH,adsorption time,initial Pb2+ concentration and adsorption temperature on the adsorption effect were studied by the adsorption experiment of SH-MWCNTs.We had studied the adsorption kinetics,adsorption isotherm characteristics and adsorption thermodynamics.The results showed that the adsorption time was 60 min and the p H was 5,and the adsorption capacity was the best.The adsorption capacity increased with the increase of Pb2+ concentration and temperature.The adsorption kinetics,adsorption isotherm and adsorption thermodynamics showed that the kinetics are inaccordance with the quasi-second order linear equation.The adsorption isotherm conforms to the Langmuir model.It is mainly for the monolayer adsorption and adsorption thermodynamics.It is found that the reaction is an endothermic reaction.The heating is favorable for the adsorption and it is also an spontaneous reaction.Based on the above results,it can be seen that sulphydryl multi-walled carbon nanotubes can effectively remove heavy metal cadmium and lead in water,the pH of solution,the dosage of adsorbent,the time of adsorption,the initial heavy metal ion concentration and the adsorption temperature are the factors affect the adsorption results.And the adsorption mechanism of the heavy metal ions in the water can be further investigated by studying the adsorption kinetics,the adsorption isotherm and the adsorption thermodynamics.Sulphydryl multi-walled carbon nanotubes are a kind of ideal adsorbent material,which has broad development potential and application prospect.