Detoxification of Organophosphorus Compound from Water with Mesoporous Silica

Organophosphorus pesticides are a group of dangerous substances that were widely used as warfare agents or agricultural pesticides. The aim of this experimental study was to investigate the detoxification of diazinon pesticide (as a model of organophosphorus compounds) from water with mesoporous silica.
The mesoporous silica was produced via sol-gel method and characterized its structure by using XRD, FTIR, BET and SEM techniques. Adsorption tests were carried out in a batch system to study the effect of various parameters (pH, contact time, adsorbent dose and initial concentration) on the detoxification. Also, the kinetic and adsorption isotherms have been investigated in this study.
The results showed that the maximum adsorption capacity (135 mg/g) based on Langmuir adsorption isotherm is at pH=6, initial concentration 50 mg/L, 50 min and adsorbent dose 0.1 g/L, and also the maximum removal percentage (72%) was obtained at adsorbent dose 10 g/L. The adsorption isotherm and kinetic model were obtained to be conforming to Langmuir model and pseudo-second order, respectively.
Based on the high adsorption capacity of mesoporous silica for diazinon removal, it can be concluded that the mesoporous silica is an effective adsorbent for detoxification of organophosphorus pesticides from water.