Studies On The Adsorption Property Of Modified Diatomite And Nanosized MnO₂/Diatomite To Phenolic Wastewater

The acid-activated diatomite was modified by dodecyltrimethyl ammonium bromide (DTAB) and the nanosized MnO2 and nanosized MnO2/diatomite samples were prepared via sol-gel method using Mn (COOCH3)2 and citric acid. Taking the removal ratio of modified diatomite, nanosized MnO2, nanosized MnO2/diatomite to phenol as the main index respectively, the adsorption conditions was investigated and optimized. The main work and results are as follows:(1) Taking the removal ratio of phenol as the main index, the adsorption property and conditions of modified diatomite were investigated via single-factor and orthogonal experiments. The adsorption conditions were optimized as follows:adsorption temperature 20℃, adsorption time 2h, pH value 7 and the dose of the adsorbent 2g·L-1 respectively. The removal ratio of phenol under the optimized conditions can reach 69.6%.(2) Taking the removal ratio of phenol as the main index, the adsorption property and conditions of the nanosized MnO2 were investigated via single-factor and orthogonal experiments. The adsorption conditions were optimized as follows:adsorption temperature 20℃, adsorption time 60min, pH value 3 and the dose of the adsorbent 0.45g·L-1 respectively. The removal ratio of phenol under the optimized conditions can reach 76.03%.(3) Taking the removal ratio of phenol as the main index, the adsorption property and conditions of the nanosized MnO2/diatomite were investigated via single-factor and orthogonal experiments. The adsorption conditions were optimized as follows: adsorption temperature 20℃, adsorption time 100min, pH value 3 and the dose of the adsorbent 0.45g·L-1 respectively. The removal ratio of phenol under the optimized conditions can reach 86.5%.(4) The adsorption isotherm of acid-activated diatomite and modified diatomite to phenol can be described by the Freundlich model while that of nanosized MnO2 and nanosized MnO2/diatomite to phenol can be described by the Langmuir model, with the maximum adsorption capacity of 12.15mg·g-1,26.1mg·g-1, 161.8123mg·g-1, 207.0393mg-g"1 respectively.