Preparation Of Activated Carbon-Based Composite Adsorbent And Its Adsorption Mechanism Of Organic Matter

Activated carbon is widely used to remove micropollutants in water because of its simplicity and low cost.Powdered activated carbon（PAC）has a larger contact area,stronger adsorption capacity,and more significant effect.However,it has the problems of limited adsorption effect on hydrophilic and lipophilic molecules and difficulty in rapid solid-liquid separation.Based on this,this study used PAC,humic acid（HS）and aluminum potassium sulfate（APS）as raw materials to successfully prepare powdered activated carbon-based composites PACC by chemical precipitation method,and used it as methylene blue（MB）And the purification adsorbent of oily sewage.And carried out Fourier transform infrared spectroscopic analysis,scanning electron microscopy and elemental analysis,particle size distribution analysis,zero charge point analysis and X-ray photoelectron energy spectrum analysis to it,the result shows that PACC has layered porous structure and active functional group,is beneficial to Transport diffusion and chemisorption of MB and oil.The adsorption performance of PACC on MB and organic matter in oily sewage was also studied through static adsorption experiments.The main research results are as follows:PACC showed a stronger adsorption capacity for MB,with a removal rate of 99.02%;the adsorption equilibrium time was 750 min;in the alkaline environment of p H=11,the adsorption effect of PACC was better,(q_e=794.39 mg·g^-1,C₀=500 mg·L^-1);the pseudo-second-order kinetic model and the Langmuir adsorption isotherm model fit well,indicating that the adsorption process involved chemical adsorption;thermodynamic data indicated that the adsorption was a spontaneous endothermic process.Infrared characterization results confirmed the formation of hydrogen bonds when PACC adsorbed MB;the adsorption mechanism included charge interaction,hydrogen bond interaction and van der Waals force.During the process of PACC adsorbing oily sewage,PACC has a stronger adsorption capacity for oily sewage than PAC;after 750 min,the active sites on PACC are basically saturated with organic pollutants;The oil removal rate reached 95%;the pseudo-second-order kinetic model and the Langmuir adsorption isotherm model fit well,with R2 being 0.99805 and 0.99178 respectively;the adsorption process was a spontaneous exothermic process;infrared results confirmed that PACC and oily sewage form hydrogen bonds;adsorption mechanisms include hydrophobic forces,electrostatic attraction,and hydrogen bonding.