Amir Masoud Samani Majd

Benzene removal by nano magnetic particles under continuous condition from aqueous solutions

Benzene removal from aqueous solutions was evaluated using Fe3O4 nano magnetic particles (NM) in continuous condition. A 44 factorial design including initial benzene concentration, NM dose, contact time and pH was investigated in 16 experiments (Taguchi OA design). The results indicated that all factors were significant and the optimum condition was: pH 8, NM dose of 2000 mg·L−1, benzene concentrations of 100 mg·L−1 and contact time of 14 min. The maximum benzene uptake and distribution ratio in the optimum situation were 49.4 mg·g−1 and 38.4 L·g−1, respectively. The nano particles were shown to capture 98.7% of the benzene in optimum batch condition and 94.5% in continuous condition. The isotherm data proved that the Brunauer-Emmett-Teller model fit more closely and produced an isotherm constant (b) less than one, indicating favorable adsorption. Regeneration studies verified that the benzene adsorbed by the NM could be easily desorbed by temperature, and thereby, NM can be employed repeatedly in water and wastewater management.

Degradação da Matéria Orgânica Natural Utilizando Processos Combinados de Ultrassom e Tratamento Com Peróxido de Hidrogênio

The purpose of this study was to explore and examine an advance oxidation process using ultrasonic (US)/H2O2 as a potential treatment and removal of humic acid (HA). The US power, HA concentration and H2O2 concentration enhanced removal process was performed by varying the irradiation time, the preliminary experiments demonstrated that natural organic matter (NOM) and HA removal was influenced by the power, HA concentration and time of sonication. The optimum conditions for HA and NOM removal were achieved by US irradiation of 110 W power, at 20 min contact time, and 20 mg.L-1 of HA concentration. Likewise, the optimum conditions for HA and NOM removal with hydrogen peroxide were obtained at 120 min time and 10×10-3 mol.L-1 of H2O2. The results indicated a strong capacity of sonication for NOM and HA removal, therefore by adding H2O2 to the aqueous solution increased NOM and HA removal by US. The HA removal efficiency of US/H2O2 (91.5%) was more than US (69.3%) and H2O2 (20%). US/H2O2 system proved to be the most effective. The sonochemical degradation with US/H2O2 can be an efficient method to remove the NOM from aqueous solution and may be a realistic possibility for large-scale treatment.The purpose of this study was to explore and examine an advance oxidation process using ultrasonic (US)/H 2 O 2 as a potential treatment and removal of humic acid (HA). The US power, HA concentration and H 2 O 2 concentration enhanced removal process was performed by varying the irradiation time, the preliminary experiments demonstrated that natural organic matter (NOM) and HA removal was influenced by the power, HA concentration and time of sonication. The optimum conditions for HA and NOM removal were achieved by US irradiation of 110 W power, at 20 min contact time, and 20 mg.L -1 of HA concentration. Likewise, the optimum conditions for HA and NOM removal with hydrogen peroxide were obtained at 120 min time and 10A—10 -3 mol.L -1 of H 2 O 2 . The results indicated a strong capacity of sonication for NOM and HA removal, therefore by adding H 2 O 2 to the aqueous solution increased NOM and HA removal by US. The HA removal efficiency of US/H 2 O 2 (91.5%) was more than US (69.3%) and H 2 O 2 (20%). US/H 2 O 2 system proved to be the most effective. The sonochemical degradation with US/H 2 O 2 can be an efficient method to remove the NOM from aqueous solution and may be a realistic possibility for large-scale treatment.

Avaliação Qualitativa da Água Engarrafada e Armazenadas em Frascos de Tereftalato de Polietileno com Base Compostos Químicos Orgânicos

Polyethylene terephtalate (PET) is commonly used for bottling drinking water. PET must be harmless in the sense of the migration potentially unsafe materials into its content. The quality determination of migrated organic chemicals in 15 bottled water stored in PET was performed by gas chromatography-mass spectrometry technique. Most of the organic chemical compounds including phthalate, alkyl phenol, higher alkene and organic acid were detected in the samples. However, no carcinogens and hormones were recognized in the analyzed waters. The most migrated compounds identified between 13 to 100% of bottled water. The findings of present study could be alarming for the food safety legislative establishments in Iran due to the existence of some organic compounds with adverse influence on human wellbeing. Further investigation is recommended to evaluate the risk assessment of the public health arising from the presence of these toxic contaminants in the bottled water consumed by the people.

An Investigation of Ammonia Extraction from Liquid Manure Using a Gas-Permeable Membrane

Abstract: Pollution of air, soil and water caused by excessive ammonia (NH3) emission and deposition from animal manure is as an environmental concern. Gas-permeable membranes (GPM) may provide a solution for controlling NH3 emission to the environment by extracting it from liquid manure and potentially using the recovered NH3 as fertilizer. For this purpose, four lab-scale experiments were conducted to investigate the capture and recovery of NH3 from liquid manure by circulating an acid solution through a tubular GPM submerged into the liquid dairy manure. During these experiments, the depth of liquid manure in chambers of different dimensions and the tubular membrane parameters including diameter, length and pore size were held constant in order to study the effect of acid-filled membrane on NH3 extraction from different surface areas (1X, 2X, 4X, and 8X) of liquid manure. Results show that nearly 50% of the liquid manure NH3 measured prior to the start of each experiment from all but 8X chamber was captured in less than 20 days by acid-filled membranes. Also, NH3 extraction by the GPM system from liquid manure and NH3 gain in acidic solution were linearly correlated. The study showed that the experiment with the 4X chamber resulted in optimum NH3 extraction using the GPM system.

Removing ammonia from air with a constant pH, slightly acidic water spray wet scrubber using recycled scrubbing solution

Previous research on wet scrubbers has only studied highly acidic scrubbing solutions because of their high ammonia capture efficiencies; however, the high acidity created practical problems. Lower acidity solutions would reduce corrosion, maintenance, and cost; however, designers may need to use strategies for increasing scrubber effectiveness, such as using lower air velocities. The objective of this study was to determine if a spray scrubber with slightly acidic and higher pH scrubbing solution (pH from 2 to 8) could effectively remove NH3 from NH3 laden air (such as animal building exhaust air), and also collect this valuable resource for later use as a fertilizer. A bench-scale spray wet scrubber treated 20 ppmv NH3/air mixture in a countercurrent contact chamber. First, the solution pH was varied from 2 to 8 while maintaining constant air velocity at 1.3 m•s–1. Next, air velocity was increased (2 and 3 m•s–1) while solution pH remained constant at pH6. At 1.3 m•s–1, NH3 removal efficiencies ranged between 49.0% (pH8) and 84.3% (pH2). This study has shown that slightly acidic scrubbing solutions are a practical means of removing ammonia from air especially if the scrubber is designed to increase collisions between solution droplets and NH3 molecules. The NH3 removed from the air was held in solution as NH4+ and accumulates over time so the solution should be an excellent fertilizer.

Application of Diluted Sulfuric Acid for Manure Ammonia Extraction Using a Gas-Permeable Membrane

Tubular gas-permeable membrane (GPM) provides an alternative solution for ammonia (NH3) mitigation and recovery from liquid animal manure. A set-up consisting of a closed dairy liquid manure (LM) chamber, two sulfuric acid (H2SO4) flasks and two GPM systems was fabricated in order to investigate NH3 extraction processes using diluted H2SO4 solutions (pH values between 2 and 5.4). One GPM system was submerged below the LM surface and the other was suspended above LM surface in the headspace of the chamber. Ammonia from dairy LM was extracted and captured in acidic solution by circulating the diluted H2SO4 through both GPM systems. Results showed that the extraction of NH3 by both systems continued for few days, even though pH of the circulating acidic solution in the tubular GPM increased above the neutral pH value. By then, between 5% and 13% of the initial NH3 concentration of untreated LM were extracted by the circulating acidic solution in both systems. It was observed that the pH of acidic solution increased very quickly; especially for more diluted acid solutions. Among all experiments, the diluted acid with pH of 2 had the greatest NH3 removal and recovery as ammonium sulfate (NH4)2SO4, a potential fertilizer. However, none of the experiments with diluted acidic solutions resulted in greater extraction and recovery of NH3 from LM as compare to the strong acid (pH<0.4) used in a previous study.