Optimization of Mercury Adsorption Process from Aqueous Solutions using Polypyrrol/clinoptilolite Composites with Taguchi Method

The release of heavy metals into the environment has caused major problems around the world due to industrialization and urbanization. The aim of this study was to examine the possibility of mercury (Hg(II)) removal from aqueous solution in batch process using synthesized functional polypyrrol/ clinoptilolite nanocomposite. The morphology and functional groups of the nanocomposites were characterized using scanning electron microscope (SEM), Fourier-transform infrared spectroscopy (FTIR) and BET. The adsorbent modified was used to remove mercury from aqueous solution. The experiments and optimization were performed based on experimental design with three levels of variables using Taguchi method. Results revealed that in mercury sorption tests in aqueous solution, pH solution has the greatest impact on the removal efficiency of mercury and mercury sorption in the alkaline conditions is more than acidic and neutral solution. The highest removal efficiency of mercury (approximately 95%) from aqueous solution with a concentration of 50 mg/l was obtained in the values ​​of the third level of the operational variables pH, contact time, and adsorbent mass, which were 10, 30 min and 0.35 g, respectively. The concentration of mercury ions in aqueous solution was measured using an atomic absorption spectrometer. The study of adsorption isotherm models was performed by four isotherms of Langmuir, Friendlich, Dabinin Radskovich, and Tamkin. The results showed that the maximum adsorption capacity of mercury by polymer composite was 42.37 mg/g

Removal of Diazinon Insecticide from Aqueous Solutions by Polypyrrole onto Polyvinyl Alcohol Composite

Organophosphorus compounds are extensively used worldwide as pesticides which cause great hazards to human health and the environment. The aim of this study was to investigate the removal of diazinon insecticide from aqueous solution by using polypyrrole (PPy) onto polyvinyl alcohol (PVA) adsorbent in a batch system. Investigation of the adsorbent structure was performed by SEM and FTIR analyses. The effect of experimental parameters on adsorption such as pH, contact time, initial diazinon concentration, and initial adsorbent mass was studied. According to the experiments, the optimal pH of diazinon adsorption by PPy/PVA adsorbent at 20 °C was 6. As the contact time increased, the adsorption efficiency increased and reached equilibrium (98%) after 10 min. The adsorption capacity of diazinon increased with increasing adsorbent mass and reached its highest value in the adsorbent mass of 0.025 g in 10 ml of aqueous diazinon solution. The kinetics study showed that the data followed by Morris–Weber and pseudo-second-order equations. The equilibrium data also show good agreement with the Freundlich isotherm. Based on the results of the present study, PPy/PVA adsorbent has a high potential for diazinon pesticide removal and it can be suggested as a cheap, efficient and available adsorbent for diazinon pesticide removal from aqueous solutions. The maximum adsorption capacity of mercury by polymer composite was 23.37 mg/g

Adsorption study of Pb(II) in aqueous medium using polyaniline nanocomposites

This research work presents a simple and effective way for preparation of polyaniline (PANI) nanofiber composites mixed with polyvinyl alcohol or polystyrene (PS) and their application for lead (Pb) removal from an aqueous medium. Interestingly, PANI/PS porous nanofibers show excellent performance as a one-step Pb removal technique from aqueous solutions. The efficiency of Pb removal is found to be more than 95%, which is pretty higher than the previously reported values of other nanocomposites, as Pb removal adsorbents. Furthermore, when pure PANI nanofibers cannot remove Pb in an efficient way, this is a straightforward method for separation from the solution. This is attributable to the high surface area of PANI-PS composites. This study also provides a simple and effective way for the development of new environmental cleaning materials. The PANI/PS composite nanofiber could be a good candidate for efficient Pb removal from wastewater and for deep purification of polluted water. The composite materials have been investigated in terms of morphology, chemical structure, thermal behavior, and defect evolution using Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy, Differential Scanning Calorimetry, Thermal Gravimetric Analysis, and Positron Annihilation Spectroscopy, respectively. To measure the adsorption capacity and intensity of adsorption, the adsorption data were fitted in Langmuir, and Freundlich models. J. VINYL ADDIT. TECHNOL., 23:E99-E106, 2017. 1 2016 Society of Plastics Engineers. 1 2016 Society of Plastics EngineersScopu