Preparation Of Cellulose Palmitate And Its Application In Phenols Wastewater Treatment

With the progress of modern industry,benzene series have become the main water pollutants.Benzene series have the characteristics of being toxic and not easily degradable,and they are very harmful to animals and plants.In the conventional method for treating benzene and toluene wastewater,adsorption is the most commonly used method.In addition,cellulose-based adsorbents have a wide range of sources,low preparation costs,and strong adsorption capacity,which have become hot topics in the current research field.In this paper,the intermediates of p-tosylated cellulose were synthesized by using a co-reactant method under the homogeneous conditions using microcrystalline cellulose as raw material.Cellulose palmitate was further synthesized using palmitoyl chloride as an esterification agent.The resulting product was finally applied to the removal of benzenes?benzene and toluene?in water.First of all,p-tosylated cellulose was successfully prepared from microcrystalline cellulose in a NaOH/urea solution using p-toluenesulfonyl chloride as the activator and nonylphenol polyoxyethylene ether as the nonionic surfactant.Its properties were characterized by Fourier infrared spectroscopy,nuclear magnetic resonance spectroscopy,X-ray diffraction and thermogravimetry.Single factor experiments were designed,and then the results of elemental analysis showed that ultrasound can significantly increase the degree of substitution of the product.According to the orthogonal experiment of L₉?3?³,the best synthesis condition for p-tosylated cellulose was that the amount of nonylphenol polyoxyethylene ether was 2.5 mL,and the molar ratio of AGU/Tos-Cl was 1:7.The reaction time was 11 h and the reaction temperature was 20°C.The resulting product had a degree of substitution of 1.08 and a yield of224.47%.Secondly,cellulose esters of palmitic acid ester I and cellulose palmitate II are obtained by further esterifying p-tosylated cellulose in NaOH/urea by sonication under ultrasonic conditions using palmitoyl chloride as an esterifying agent.The cellulose palmitate I and II were characterized by FTIR,¹³C-NMR,XRD,TGA and other methods.The results showed that the cellulose palmitate synthesized by both pathways was successful.Through single-factor experiments and L₉?3?³ orthogonal experiments,it was found that the degree of substitution of cellulose palmitate I was higher than that of cellulose palmitate II under the same reaction conditions.The preferred synthesis conditions were as follows:the reaction temperature was 95°C,the reaction time was18 h,the molar ratio of AGU/Pam-Cl was 1:4,the degree of substitution of the prepared cellulose palmitate was 0.75,and the yield was 335.91%.Finally,the adsorption performance of cellulose palmitate on benzene and toluene solutions in water was investigated.The effect of the amount of product added on the adsorption capacity of benzene and toluene was discussed,as well as the adsorption kinetics and adsorption isotherm model fitting for the adsorption of cellulose palmitate.The results showed that:cellulose palmitate had good adsorption of benzene and toluene in the water.In addition,the adsorption behavior of benzene and toluene on cellulose palmitate was in accordance with quasi-second-order adsorption kinetic model and Temkinr adsorption isotherm model.The maximum adsorption capacities of cellulose palmitate to benzene and toluene were 86.22 mg/g and 96.61 mg/g,respectively.In summary,the cellulose palmitate prepared in the NaOH/urea solution is environmentally friendly.It also effectively removes benzene and toluene from the water.This research provides a theoretical basis and application basis for the development of this field.