Manmeet Kaur; Dixit Prasher; Ranjana Sharma
Abstract
The presence of various hazardous toxins such as Phenols, phthalates, pesticides, dyes, heavy metals, pharmaceutical waste, etc, is continuously increasing into the water bodies from different agricultural, industrial and domestic practices, which have brought the toxicity level to an alarming height. ...
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The presence of various hazardous toxins such as Phenols, phthalates, pesticides, dyes, heavy metals, pharmaceutical waste, etc, is continuously increasing into the water bodies from different agricultural, industrial and domestic practices, which have brought the toxicity level to an alarming height. Often, these toxic compounds are quite stable in nature and the removal or degradation of these compounds is quite challenging, which further poses a significant threat to the environment. When it comes to enhance the efficiency of water purification and decontamination process, SnO2 nanoparticles offer great potential owing to their low concentration and large surface area. Over the past few years, SnO2 nanoparticles as a photocatalyst has garnered huge interest from the researcher community towards the photo-degradation of toxic pollutants present in the water bodies. Among various metal oxides, particularly SnO2 has been emerged as the most versatile material for doping of different transition metals due to its plethora of applications such as photocatalysis, energy harnessing, sensors, solar cells and optoelectronic devices. The pure and doped SnO2 has prominent significance due to its phenomenal catalytic and physicochemical properties such as chemically stable, inexpensive and non-toxic. This review explores and summarizes the progress of first and second transition metal series doping in SnO2 for its coherent application towards the degradation of water pollutants. We have emphasized the effect of different transition metal dopants used in the growth of SnO2 nanoparticles on the basis of their synthesis technique, source of irradiation used, nature of contaminations removed and obtained photodegradation efficiency.
Hamid Kazemi Hakki; Pouya Shekari; Ahmad Najafidoust; Nosrat Dezhvan; Masoume Seddighi Rad
Abstract
Nowadays, not only the lack of water sources but also water pollution by industrial wastewater has become a major challenge. One of the pollutants of water resources, which threatens water resources, is phenol that enters the environment through wastewater from various industries such as petrochemicals, ...
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Nowadays, not only the lack of water sources but also water pollution by industrial wastewater has become a major challenge. One of the pollutants of water resources, which threatens water resources, is phenol that enters the environment through wastewater from various industries such as petrochemicals, refineries, pharmaceuticals, etc. This compound, due to its toxicity, high stability and solubility in water caused many problems and it is very important to remove it from industrial wastewater. Therefore, the main purpose of this study is to remove phenol from wastewater by using catalytic oxidation. Fe-ZSM-5 catalyst was synthesized by precipitation method and its characteristics were determined by XRD, FTIR, SEM and BET analyses. The results of XRD analysis showed that the iron ions are in the MFI structure and the catalyst has a good crystallinity phase, so that it retains its MFI structure. BET analysis showed the specific surface area of the synthesized catalyst is 293g/m2. The catalytic activity of Fe-ZSM-5 was investigated in degradation of phenol and the results showed that the mentioned catalyst had the highest removal percentage (85.82%) in 90 min at pH = 4.25 and T= 70 °C. The effect of various parameters such as ultraviolet radiation, initial pollutant concentration, catalyst loading and H2O2 concentration on the catalytic activity were also investigated.
Hossein Mohammadifard; Mohammad C. Amiri
Abstract
Heavy metals pollution in the environment is one of the serious problems in the field of water and wastewater management. In this study; calcium carbonate nanoparticles, synthesized by an efficient and novel method, were used as an adsorbent for the removal of lead and iron from aqueous solutions. To ...
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Heavy metals pollution in the environment is one of the serious problems in the field of water and wastewater management. In this study; calcium carbonate nanoparticles, synthesized by an efficient and novel method, were used as an adsorbent for the removal of lead and iron from aqueous solutions. To study the mechanism of adsorption, the kinetic and isotherm models were examined. The adsorption kinetics of process was found to follow a pseudo-second-order equation. The maximum monolayer adsorption capacities of calcium carbonate nanoparticles calculated from Langmuir isotherm were found to be 1210±30 mg/g for Pb(II) and 845±8 mg/g for Fe(II) ions, respectively. The response surface methodology based on three variable Box-Behnken design was utilized to evaluate the effects of temperature (25-65 oC) and initial metal concentration (10-200 mg/L) on the sorption process. The optimum conditions for the removal process using calcium carbonate nanoparticles were found to be 200 mg/L at 25 oC. Experimental data demonstrated that a precipitation transformation mechanism rather than adsorption enhances the removal efficiency.
Ines Bouaziz; Morched Hamza; Ridha Abdelhedi; André Savall; Karine Groenen Serrano
Abstract
The electrochemical regeneration of methylene blue-saturated activated carbon, Nyex®1000 and sawdust has been studied and the performances in terms of capacity of adsorbent regeneration have been compared in this work. The adsorption isotherms were investigated. The results showed that the adsorption ...
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The electrochemical regeneration of methylene blue-saturated activated carbon, Nyex®1000 and sawdust has been studied and the performances in terms of capacity of adsorbent regeneration have been compared in this work. The adsorption isotherms were investigated. The results showed that the adsorption of methylene blue onto the investigated adsorbents obeyed Langmuir’s model. The electrochemical oxidation of methylene blue beforehand adsorbed was studied using a boron doped diamond anode. The electrochemical regeneration efficiencies, under the same experimental conditions, of the activated carbon and Nyex®1000 were significantly less than 100% which were much lower to that of sawdust. Indeed the electrolysis tends to activate the sawdust because all the regeneration efficiencies obtained, whatever the applied current intensity, are higher than 100 %. Increasing treatment time would also result in a better regeneration of sawdust. This study confirmed that the coupling adsorption onto sawdust and electrochemical degradation is a potential technique for the efficient elimination of low concentration organic dyes from wastewater.