Preparation Of Modified Carbon-Based Adsorbent Materials And Studying On Removal Of Pb(?)

Water is one of the essential enablers of life on earth.With the rapid development of urbanization,the industrialization that has developed along with it has also brought serious heavy metal pollution.In this era of advocating the construction of a green country,it is imperative to solve the problem of water pollution.Lead is a highly toxic heavy metal which may be introduced to a water body from various sources ranging from battery to ammunition industries.Lead poses a risk to public health when consumed in drinking water,even at very low concentrations due to bioaccumulation.Carbon-based adsorbents are widely used as materials for easy acquisition and good surface properties.In this thesis,the modification of carbon materials is carried out to prepare materials with high and rapid adsorption capacity for heavy metals to achieve the removal of pollutants in water.The research results obtained are as follows:A novel 3-amino-1,2,4-triazole surface modified hydroxylcarbon nanotubes was prepared for effective removal of Pb(?)from water.The physical and chemical properties of the material were characterized using SEM and FTIR.The batch adsorption experiment results showed that the maximum adsorption capacity was 209.05 mg/g attained at 25 ?,after 300 min of contact time with equilibrium pH=6.6.The adsorption kinetic data could be well described by the pseudo-second-order model.The experimental data were subjected to Langmuir and Freundlich.It found that the adsorption process fit Freundlich isotherm mode.The adsorbent could keep effect removal efficiency after five adsorption-desorption cycles.The hydroxyl carbon nanotubes were chemically modified with 4-Amino-3-hydrazino-5-mercapto-1,2,4-triazole.The adsorbents were characterized by FTIR and SEM.The effects of pH,adsorbent dose,initial ion concentration,and temperature on adsorption efficiency were investigated by central composite design.The optimum adsorption conditions were 0.1 g/L of the adsorbents,pH=6.6 and 180 min.The pseudo-second-order model was achieved from the adsorption kinetic studies.Various adsorption isotherm models at different temperatures were examined.The results show that the Freundlich isotherm is fitted suitably for the adsorbent in this work.Moreover,desorption study revealed the favorable regeneration ability of adsorbents powders,even after 5adsorption-desorption cycles.A new synthesis method was developed to produce iron manganese–biochar composite material from sugarcane bagasse.FTIR,XRD,VSM and SEM were used to analysis the physical and chemical properties of the composite adsorbent.Batch sorption experiments were carried out to investigate the adsorption behavior of lead by iron manganese–biochar.Experimental data were better fitted by a pseudo-second-order kinetics equation and the Langmuir isotherm model.Thermodynamic analysis indicated that the adsorption process was spontaneous and endothermic.At 25 ?,the maximum adsorption capacity of the modified biochar was observed at pH=6.6 and 240 min,which was 155.49 mg/g.The adsorbed iron manganese–biochar could be effectively regenerated.