علی مهری زاد

In this research, NiO/Fe3O4 magnetic composite supported onto clinoptilolite zeolite (NiO/Fe3O4/CP) was synthesized and characterized by different techniques such as X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectrometer (EDS) and vibrating-sample magnetometer (VSM). The feasibility of employing NiO/Fe3O4/CP as a catalyst in the catalytic ozonation of dairy effluent was investigated. The effect of four effective operational parameters (catalyst dosage, pH, ozone dosage and time) was investigated. Based on the obtained results, increasing the catalyst and ozone dosage play a vital role in increasing the COD removal efficiency of effluent. The effect of solution pH also showed that the COD removal efficiency of dairy effluent in alkaline solutions is higher than acidic solutions, which can be attributed to the presence of hydroxyl radicals in alkaline environments and their high oxidizing power. The kinetic studies demonstrated that the presence of the NiO/Fe3O4/CP ternary composite in the catalytic ozonation process leads to a doubling of the reaction rate compared to the ozonation process.

In this research, BFO/g-C3N4 nanocomposite was prepared via the hydrothermal method and was analyzed by FTIR, XRD, FESEM, Dot mapping, and EDS. BET and BJH techniques were used to determine the specific surface area and pore size of BFO/g-C3N4 nanocomposite. The efficiency of BFO/g-C3N4 nanocomposite as a photocatalyst was evaluated on photocatalytic degradation of Congo Red dye under visible light irradiation. The effect of key factors, i.e., time, pH of the solution, initial Congo Red concentration, and BFO/g-C3N4 dosage, was studied on photocatalytic degradation of Congo Red dye. Results revealed that degradation of Congo red is increased by increasing time and BFO/g-C3N4 dosage and is decreased by increasing Congo Red concentration and pH. The maximum removal percentage of Congo red reached 74.66% at 40 min, pH=2, initial dye concentration of 10 mg/L, photocatalyst dosage of 0.05 g/100mL under 30 w visible light. It can be deduced that BFO/g-C3N4 nanocomposite act as an effective photocatalyst for removing Congo red from aqueous solutions when exposed to visible light.

Tetracycline (TC) is one of the most prevalent antibiotics which is used to treat the infectious diseases. Entrance of this pharmaceutical compound to the environment can lead to numerous problems. Therefore, this study was conducted with the aim of evaluation of the removal efficacy of TC by sonocatalytic process using samarium-doped zinc sulfide (Sm-ZnS). In this study, Sm-ZnS nanoparticles were synthesized through an ultrasound-assisted co-precipitation method and were used for sonocatalytic degradation of TC. The sonocatalytic experiments were conducted in a flask equipped with a water bath under the ultrasonic (US) waves resulting from a probe at different operational conditions. The results showed that the degradation efficiency increases with the increase of catalyst amount (0.2-1 g/L), US power (30-50 W) and time (10-30 min), and reduces with the increment of the TC initial concentration (10-30 mg/L). Modeling and optimization of the process by response surface methodology revealed that under the optimum conditions ([TC]0= 15 mg/L, [Sm-ZnS]0= 0.4 g/L, US power= 45 W and t= 15 min), degradation efficiency reached 97%. Kinetics studies showed that the sonocatalytic process follows the pseudo-first-order model with the rate constant of 0.223 min-1. Based on the results it can be concluded that the sonocatalytic process using Sm-ZnS catalyst can be used as an effective and available method to remove TC from sewage and pharmaceutical wastewater.

Methylene blue dye is the most common dye for dyeing cotton, wool and silk. Inhalation of this dye can cause respiratory distress and while direct exposure to it can also cause permanent eye damage, burning sensation in the exposed areas, Nausea and vomiting, excessive sweating and mental disorders. In this paper, silver nanoparticles was synthesized via a simple method. Various techniques such as FESEM, XRD, UV-Vis DRS were used to identify the morphology, structural composition and optical properties of synthesized silver nanoparticles. The results of UV-Vis DRS showed that the prepared silver nanoparticles effectively improved the efficiency of the visible light response in the process of photocatalytic degradation of methylene blue dye. The results of pseudo-first-order linear kinetics showed that the value of k increased with increasing of MB dye concentration from 0.0264 to 0.0614 min-1. In general, nano-silver synthesis showed a high potential in removing MB dye from aqueous solutions.

In this research, samarium doped cadmium sulfide (Sm-CdS) nanoparticles were prepared through an ultrasound-assisted co-precipitation method. The synthesized sample was characterized by XRD, UV-Vis, ICP-OES and TEM techniques. The photocatalytic performance of the Sm-CdS was evaluated through the degradation of Rhodamine 6G (Rh-6G) under visible light irradiation. The effect of operational parameters on the degradation efficiency was modeled and optimized using response surface methodology (RSM). Under the optimal conditions ([Dye]0= 4 mg/l, [Catalyst]0= 0.6 g/l, pH= 8 and t= 70 min), more than 85% of the dye molecules were degraded. The results of the reusability of the photocatalyst showed that a negligible change in the photocatalytic activity was occurred after four reuses. Byproducts resulting from the photocatalytic degradation of Rh-6G were identified using the GC-MS technique.

Dairy industries are one of the major sectors consuming huge amounts of water converting into effluents during various processes. Dairy effluents contain complex organic matters which are not easily degraded by simple methods. Hence, dexterous and effective techniques are required to treat these types of wastewater. In this regard, advanced oxidation processes like ozonation are an emergent approach to ameliorate the wastewater treatments. Ozone (O3) is a powerful oxidizer, and the strong electrophilic nature of O3 enables it to react with various organic compounds. In the ozonation process (OP), the reaction between O3 and pollutants can be explained by direct or indirect reactions, i.e. through the reaction with O3 or decomposition of O3 molecules and formation of hydroxyl radicals (°OH).The Box-Behnken method based on RSM was employed in the planning stage of the experimental approach, and the results indicated that under optimal conditions, the maximum CODr efficiency of 55.95% was obtained that was verified experimentally.

Aromatic aldehydes are toxic compounds present in different waste-waters coming from the chemical and petrochemical industries. Their environmental fate may end up by their occurrence in the ground water through the infiltration/deep percolation processes of rain and snow water. Therefore, this kind of substances is contained not only in various industrial wastewaters, but occasionally also in drinking water. Hence, the degradation of such compounds in water and wastewater is still of special interest for many researchers. Benzaldehyde is an aromatic aldehydes used chiefly as a precursor to other organic compounds, ranging from pharmaceuticals to plastic additives and it has been classified as a hazardous substance by the United States Environmental Protection Agency. As a result, the use of alternative treatment technologies, aiming to mineralize or transform refractory molecules into others which could be further biodegraded, is a matter of great concern. Among them, advanced oxidation processes (AOPs) have already been used for the treatment of water and wastewater containing recalcitrant organic compounds such as pesticides, surfactants, colouring matters, pharmaceuticals and endocrine disrupting chemicals. Moreover, they have been successfully used as pretreatment methods in order to reduce the concentrations of toxic organic compounds that inhibit biological wastewater treatment processes. The main mechanism of AOPs function is the generation of highly reactive free radicals. Hydroxyl radicals (HO•) are effective in destroying organic chemicals because they are reactive electrophiles (electron preferring) that react rapidly and nonselective with nearly all electron-rich organic compounds. They have an oxidation potential of 2.33 ev and exhibit faster rates of oxidation reactions comparing to conventional oxidants such as O3. The diverse methods used for generating these radicals are photo catalysis and sonochemistry methods. A new alternative sonochemistry approach offers a solution for combating the persistent water and wastewater organic pollutants. Sonochemical degradation could be used for organic pollutant removal in aqueous solutions. The advantages of using ultrasound irradiation are the simplicity of its use , the ultrasound does not require additional chemicals, and it can be used for treatment of turbid solutions. In this research, ultrasonic/H2O2 advanced oxidation process has been studied for degradation of aqueous solution of benzaldehyde. The effect of key parameters such as ultrasonic frequency, ultrasonic amplitude, time, pH of solution and initial concentration of the benzaldehyde on the removing rate of benzaldehyde are investigated. Different concentrations of benzaldehyde and H2O2 were prepared and the solutions were exposed to ultrasonic treatment (UP 400S model). The experiments was carried out in a batch reactor for 60 min and each 5 min an aliquot was taken from the solutions. Absorbance of sampling solutions was recorded by UV-Vis spectrophotometer of Hack (DR 5000-15 V model). The results show that, the removal rate increases with the increase of time, ultrasonic frequency and amplitude and decreases with the increase of solution pH, H2O2 and benzaldehyde concentrations. As data shown, the degradation of benzaldehyde in ultrasonic/ H2O2 process best fitted by pseudo first order kinetic. It can be conclude the combined of ultrasonic/ H2O2 led to 91% degradation of benzaldehyde after 60 min.

This research was studied the efficiency of kaolin and modified kaolin with cetyltrimethylammonium bromide and tetrabutilammonium iodide surfactants as adsorbents in the adsorption of 4-chloro-2-nitro phenol. Batch adsorption studies were carried out to study the effect of important parameters using response surface methodology (RSM). Results showed that the modification of kaolin with cetyltrimethylammonium bromide was enhanced the removal efficiency (>50%). As results, increasing of adsorbents amount in acidic media due to increase of 4-chloro-2-nitro phenol removal. Evaluation of the interplay of variables showed that interaction between initial concentration-pH and adsorbent amount-pH have the most influence on the adsorption onto kaolin, and also interaction between adsorbent amount-contact time and adsorbent amount-pH have the most influence on the adsorption of 4-chloro-2-nitro phenol onto modified kaolin with cetyltrimethylammonium bromide and tetrabutilammonium iodide, respectively.

This work describes the photocatalytic removal of methylene blue from aqueous solution by titanium dioxide nanoparticles under ultraviolet irradiation in a batch system. The effect of operational parameters such as irradiation time, nano titanium dioxide dosage, pH and initial methylene blue concentration were analyzed and optimized by response surface methodology in the nano titanium dioxide/ultraviolet irradiation process. As results, the predicted values were best fitted with the experimental data (R2 = 0.9736). The maximum removal efficiency was in the following conditions: irradiation time of 31.5 min, nano titanium dioxide dosage of 1.19 g L-1, pH of 7.8 and initial methylene blue concentration of 4.5 mg L-1. Under the optimized status, the removal yield was obtained more than 80%. Carrying out the experiment under this optimum condition resulted in the same removal efficiency, which indicated the success and suitability of the central composite design model for the optimization of the process. Prog. Color Colorants Coat. 9 (2016).

In this research work , the practice and feasibility studies have been carried out concerning the application of US, H2O2 and US/H2O2 as an AOPs, to remove some trace concentrations of reactive Blue 21.Experiments were carried out to remove the colour at different concentrations, PHs of solution and frequency factor of ultrasonic applied. A maximum deterioration of dye was shown to happen at output power of 60 kW, frequencies of 1kHz and trace concentrations in acedic or neutral media with ultrasonic technique. Due to the high amounts of hydroxyl radicals produced , the degradation of dye happened very rapidly in solutions containing some amounts of H2O2 only , and the same for both neutral and allkaleic medium . Moreover, it was found that the hundred percent of dye removal occurs using a combined system of US/H2O2.

In this research, initially modified nano-TiO2 was prepared from salicylic acid. Then, adsorption capacity of Methylene Blue (MB) onto modified nanoparticles was investigated in a batch system by considering the effects of various parameters like contact time, adsorbent dosage, pH, initial dye concentration and temperature. Optimum conditions for MB adsorption were found to be neutral and alkaline pHs, 0.4 g of adsorbent and equilibrium time≈ 50 min. The results showed that the increase of temperature and initial MB concentration leads to gradual decrease of adsorption rate. Evaluation of non-linear adsorption isotherm and kinetic models by Polymath software suggested that data can be well described by the pseudo-second-order kinetic and Freundlich isotherm models. Thermodynamic studies showed that the adsorption process was spontaneous and exothermic.

In this study, the adsorption of 4-chloro-2-nitro phenol (4C2NP) onto bentonite (B) and modified bentonite by tetra-butyl ammonium iodide (TAI) and cetyltrimethyl ammonium bromide (CTAB) from aqueous solutions by considering the effects of various parameters such as contact time, adsorbent dose, pH, initial concentration of 4C2NP and temperature was studied in a batch system. An optimal condition for uptake C2NP was reached at pH≈ 5.8, 1 g of raw and modified bentonite in 60 and 10 min of equilibrium time, respectively. The results showed that increasing the initial concentration of 4C2NP, leading to a gradual increase in adsorption.

In this research, the efficacy of titanium dioxide nanoparticles in the presence of visible light and induced visible light for the removal of reactive blue 21 from aqueous solutions was investigated. The experiments were studied in a box with visible and fluorescent light bulbs, to study the effect of various parameters such as irradiatioin time, amount of catalyst, pH, initial concentration and temperature. The results showed that the performance of nano-TiO2/induced visible light system is better than nano-TiO2/visible light. Operational parameters showed that in nano-TiO2/induced visible light system at irradiation time of 10 min, the amount of 1 g of the catalyst and an alkaline media (pH =9) dye removal efficiency was over 40%. Also, the results showed that the removal efficiency decreased with increasing the dye concentration. Kinetic studies showed that the removal of reactive blue 21 by nano-TiO2/induced visible light system obeys zero-order model. In other words, the color removal rate is independent of concentration.

In this research، adsorption capacity of Methylene Blue (MB) onto Nano-TiO2 modified by Salicylic acid from aqueous solutions was investigated in a batch system by considering the effects of various parameters like contact time، adsorbent dosage، pH and initial dye concentration. Optimum conditions for MB adsorption were found to be initial pH≈7، modified Nano-TiO2 dose≈ 0. 4 g and equilibrium time≈ 50 min. The results showed that the increase of initial MB concentration leads to gradual increase of adsorption rate.

In this research، adsorption capacity removal of 4-chloro-2-nitrophenol (4C2NP) from aqueous solutions using carbon nanofibers (CNFs) was investigated in a batch system by considering the effects of various parameters like contact time، adsorbent dosage، pH and initial concentration. Optimum conditions for (4C2NP) adsorption were found to be initial pH≈6. 04، nanofiber (CNF) dose≈ 0. 01 g and equilibrium time≈ 2 min. Results show that removal efficiency of the 4C2NP increased by increasing (4C2NP) concentration and decreased by increasing the dosage of CNFs and pH.

This project was performed out in study of degradation of 2-CEPS with nanosized ZnO under different conditions. Degradation of 2-chloroethylphenylsulfide with nanosized and non-nanosized ZnO under different conditions has been studied using GC and GC-MS. Experiments were carried out upon different samples of ZnO (dry and wet nano and non-nanosized) under ultraviolet radiation and absent of it. On the surface of the very reactive ZnO particles, 2-chloroethylphenylsulfide undergoes degradation reaction to yield 2-hydroxyethylphenylsulfiede, 2-ethoxyethylphenylsulfde, and vinylphenylsulfide as products. The results show that the maximum degradation of 2-chloro ethylphenylsulfide is obtained on the surface of wet nanosized ZnO in present of UV.