The Journal of

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Abstract

Introduction: Many industries such as manufacturers of pesticides, paints and pharmaceutics  produce large amounts of 2,4,6-Trichlorophenol (TCP). Due to its high toxicity and environmental pollution TCP is classified as a leading hazardous compound. The aim of this study was to investigate the TCP removal by using zeolite (clinoptilolite) modified with surfactants from the aqueous solutions.

Methods: In this study, the granulated and modified zeolite with surfactant Hexadecyltrimethyl Ammonium Chloride were investigated through the impact of the parameters such as pH (3, 5, 7 and 9), time (5 to 240 min), initial concentration of TCP (50 to 200 mg/L), and adsorbent dose (10 to 60 grams per liter) in a batch laboratory scale. The concentration of TCP was measured using a UV-vis  Spectrophotometer at the wavelength of 517 nm.

Results: Results showed that TCP uptake reaches equilibrium after 45 minutes and with increasing concentrations of 50 to 200 mg/L, the absorption rate of 4.04 mg/g to 12.22 mg/g can be increased. According to the results, the amount of TCP adsorption capacity at pH 3, 5, 7 and 9 was 7.02, 7, 4.76 and 4.16 mg per gram, respectively. Increasing the dose absorption of 10 to 60 g/L at constant TCP concentration 200 mg/L also increased the removal efficiency of 60.41% to 87.29% and reduced the absorption capacity of 12.78 mg/g to 2.85 mg/g. Data also showed that the Langmuir isotherm (R²=0.989) and pseudo second-order kinetic (R²>0.99) are compliance.

Conclusion: The results of the study showed that the Iranian modified zeolites can be used effectively in removal of TCP in comparison with other parts of the world. Considering the cost, availability and ease of modification, it can be used to remove TCP in water and wastewater.

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Introduction: Pharmaceutical wastes are in group of emerging contaminants. These materials cannot be removed completely with conventional treatment methods of water and wastewater. Drug and its metabolites, due to the potential risks toxic and toxicity potential to humans and environment should be removed from the water resources. In this study, Acetaminophen photo catalytic removal from aqueous solutions was investigated by X zeolite modified with TiO₂ (TiO₂/ X zeolite).

Methods: This study was experimental and carried out on a laboratory scale. To remove acetaminophen from aqueous solution, TiO₂/X zeolite photo-catalyst under UV-C radiation (UV/TiO₂-X process) was used. Acetaminophen concentration of soluble was measured using by spectrophotometer UV/Vis in λ_max ~ 243nm. The optimal conditions of pH, catalyst dosage, acetaminophen initial concentration and reaction time were determined and also acetaminophen disintegration reaction kinetics was studied by TiO₂-X catalyst. Data analysis was performed using descriptive statistics.

Results: The results indicated that maximum removal of acetaminophen(95.45%) was related to 1 mg/L of initial concentration in the neutral pH and a catalyst concentration of 500 mg/L after 75min of start of photo-catalytic reaction. By decreasing concentration of acetaminophen its removal rates will increase. The Acetaminophen degradation kinetic with UV/TiO₂-X process followed a pseudo-first order reaction with rate constants of  0.01446 min^-1.

Conclusion: The Photocatalytic method of UV/TiO₂-X to remove acetaminophen from aqueous solutions has a high efficiency and is recommended

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Introduction: Heavy metals owing to their health hazards and high toxicity in low concentration for human and environment have very concern and attention. Slow sand filter is one of the simple and cost-effective for removal of these pollutants. In this method, media play an important role for removal of pollutant. Therefore, the aim of this study was investigation of different media like slag, zeolite, and conventional media in slow sand filter for removal of lead and cadmium.

Methods: In this research there are three beds filter include typical filter bed, slag and zeolite that used in pilot plant for investigation of lead and cadmium removal at three concentration of 0.1T 1 and 10 ppm. Each of filters has an internal diameter of 8 cm and a height of 120 cm with Plexiglas, which have a continuous flow operation.

Results: The removal efficiency of turbidity by three typical filter bed, slag, and zeolite with initial turbidity of 13 NTU was 46%, 77%, and 89% respectively. Removal efficiency of lead without turbidity was 70.3%, 79%, and 59.8% respectively for 0.1 ppm lead. For 1 ppm, concentration of lead removal efficiency was 51.8%, 52.7% and 52.6% respectively and for 10 ppm it was 53.4%, 57.8%, and 59.8% respectively. Cadmium removal for these media was 23.4%, 37.5%, and 59.4% respectively at 0.1 ppm cadmium. At 1 ppm of cadmium concentration, it was 37.9%, 45% and 41.3% respectively and at 10 ppm concentration of cadmium it was 68.3%, 68.6% and 67% respectively.

Conclusion: Slag and zeolite beds are more efficiently than the conventional sand beds in the slow sand filter, so it can be used instead of the usual sand for removing lead and cadmium from resources water.

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Introduction: Ammonia in form of ammonium ions is toxic and could decrease the dissolved oxygen in water and endanger the aquatic life. The aim of this study is the removal of ammonium using oxidation and adsorption by catalytic ozonation and clinoptilolite zeolite, respectively.
Methods: The research method is Experimental. First, optimal pH of ammonium adsorption on carbon catalyst (5 g/L), Garmsar and Firoozkooh zeolites and oxidation were determine. Then, in catalytic ozonation process, the effect of other variables on ammonium removal efficiency such as the concentration of carbonic catalyst (0.5- 50 g/L) and the reaction time were investigated. Then the effect of retention time and adsorbent concentration on adsorption of the remaining ammonium and nitrate produced by the oxidation process using zeolites and their modifications were determined.
Resuts: The results showed that optimum pH for the ammonium adsorption process by carbon catalyst, catalytic ozonation and zeolite was 8, 9 and 8, respectively. However, the optimum pH 4 was determined for nitrate removal. The highest ammonium absorption capacity was related to natural Firoozookh zeolite and 18.5 mg/g, and the effect of ligand and acid modification decreased 12 and 14% of absorbed capacity, respectively. It is also, the highest nitrate removal efficiency was related to Garmsar ligand modified zeolite (98%) and an absorption capacity of 11.2 mg/g. In the COP/absorption process the concentration of ammonium was decreased to 0.6 m /L.
Conclusion: This method effectively eliminates ammonium, and the modification of zeolite with cationic surfactant increases the efficiency of nitrate removal and the concentrates of all pollutants are brought below standards.
 

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Introduction: Dyes are materials with a complex structure that enter the environment from textile processes such as dyeing and washing. The aim of this study was to investigate the efficiency of the absorption process using Zeolite @ ZnO in removing methylene blue dye from textile wastewater.
Methods: The structure and morphology of nanoparticles were examined using XRF, FTIR and FESEM techniques. Dye concentrations were determined using a spectrophotometer at 664 nm. In this study, the variables of reaction time, solution pH, adsorbent amount, and dye concentration were evaluated. To determine the isotherm and adsorption kinetics, two isotherm models of Langmuir and Freundlich ,and two kinetics models pseudo-first order ,and pseudo-second order were used.
Results: It was found that optimal conditions were concentration of 50 mg/l, adsorbent dose of 1 g/l, pH of 11, and a reaction time of 60 minutes.  The removal efficiency under optimal conditions for methylene blue was 95.8%.
Conclusion: The results of the isotherm and absorption kinetics study for methylene blue showed that the adsorption process follows the Langmuir isotherm and quasi-quadratic kinetics. The maximum adsorption capacity of the adsorbent was determined to be 384 mg/g using the Langmuir model.