فهرست مطالب

Advances in Environmental Technology
Volume:8 Issue: 3, Summer 2022

  • تاریخ انتشار: 1401/08/17
  • تعداد عناوین: 6
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  • Amir Naghizadeh, MohammadAli Salehi *, Leila Mivehi Pages 169-183

    The electrospinning technique is utilized to physically load Fe3O4/TiO2/Ag nanoparticles on polycaprolactone/polyethylene glycol (PCL/PEG) nanofibers scaffold for oxidative decomposition of 2, 4-dichlorophenol as a model organic pollutant. The scaffold is used in order to eliminate the need for separation of the catalyst after treatment, thus, making the catalyst system recyclable and reusable. Prepared nanofibers were thermally processed to change the morphology to crystalline form to make them transparent to visible light, which is a necessity for the function of photocatalysts. Different analysis techniques such as X-ray diffraction (XRD), transmission electron microscopy (TEM), UV/Vis spectrophotometry (UV–Vis), and field emission electron microscopy (FESEM) were implemented to identify and characterize the presented products. Kinetic performance of both the particulate system and nanofiber system was determined. The prepared products demonstrated good catalytic activity by 53%, decomposing the target pollutant in 180 minutes of visible light exposure. The new catalyst-loaded nanofiber system maintained the decomposition performance of the particulate system and improved its reusability. Although this scaffold nanofiber-based system demonstrates slightly lower pollutant removal performance in the first run compared to the ternary non-fixed particle system (53.12% vs 54.74%), it outperforms the non-fixed particulate system in the 2nd and 3rd runs. The decomposition rate improved from 52.37% to 52.81% in the 2nd run and from 48.08 to 51.02% for the 3rd run. This photocatalytic system can be used as a reusable efficient catalyst for oxidative decomposing of 2, 4-dichlorophenol.

    Keywords: Electrospinning, Nanofibers, metallic nanocomposite, catalyst loaded nanofiber
  • Reza Fateminia, Soosan Rowshanzamir *, Foad Mehri Pages 185-201
    The removal of nitrate concentrations above international drinking water standards is a prominent task of governments. In this regard, various technologies such as reverse osmosis, biological denitrification, electrodialysis, and capacitive deionization (CDI) as an electrochemical approach have been used for nitrate removal from water. In the present research study, a novel composite electrode named E2 was synthesized and used to improve the efficiency of the membrane capacitive deionization (MCDI) process for increasing the electrosorption capacity of nitrate from water. E1 as a based electrode composed of activated carbon (AC), PVDF, and E2 as an optimal electrode containing (AC), PVDF, ZrO2, and PANi -ES were utilized. The morphology and structure of the composite electrode were determined using field emission scanning electron microscopy (FESEM), Brunauer–Emmett–Teller (BET), Fourier-transform infrared spectroscopy (TEM), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDAX) techniques. Also, the cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) methods were applied to investigate the electrochemical behavior of the electrodes. In the MCDI process with the presence of the E2 electrode, the amounts of separated nitrate ion and its adsorption efficiency were 7.51 mg/g and 81.6%, respectively; this demonstrated that the capacity of the adsorbed nitrate ion by the MCDI process was 30.34% higher than the CDI process. On the other hand, the E2 electrode, compared to the E1 electrode, ameliorated the performance by almost 50% of the amount of adsorbed nitrate ion and also ion adsorption efficiency during the CDI and MCDI processes.
    Keywords: Selective nitrate removal, Electrosorption, Composite electrode, Membrane capacitive deionization
  • Mahdieh Amouzegar, Ali Abbaspour *, HamidReza Asghari Pages 203-213

    Immobilization of heavy metals (HMs) by phosphorus compounds is an efficient and cheap technique in decreasing their phytoavailability in soil, depending highly on the type and rate of HMs. Greenhouse research was performed to evaluate the impact of various amendments on cadmium (Cd) absorbed by sunflower plants in HM-contaminated soil collected from a mining area. The experiment was performed as a randomized complete block design with two factors, namely mycorrhizal fungi (Rhizophagus irregularis) and amendments (di-ammonium phosphate, humic acid, bone meal, and humic acid +bone meal), in three replications. The results showed that applying all the amendments reduced the amount of soluble Cd and Cd2+ species in the soil. The highest decreases occurred with the di-ammonium phosphate treatment (51% for soluble Cd), probably through decreasing pH and increasing phosphorus solubility, as a consequence, forming insoluble Cd phosphates. Mycorrhizal inoculation significantly decreased (p≤0.05) the Cd in the soil solution and the plant shoot but increased it in the plant root, probably through Cd accumulation in the fungal hyphae as Cd phosphates. The use of phosphate compounds is strongly recommended in order to immobilize Cd in highly contaminated sites.

    Keywords: Endomycorrhizae, fungus, organic materials, phosphorus fertilizers
  • Farideh Ghaipanjeh *, Zhila Ziaei Rad, Jalal Shayegan, Mohammad Pazouki, Azarmidokht Hosseinnia Pages 215-228
    Refineries are amongst the most energy-intensive and polluting industries in the world. Biotechnology may serve as an alternative low-cost and environmental-friendly tool to the current costly, toxic and hazardous refining processes. In this study, the compositional redistribution of a heavy hydrocarbon cut is investigated under biological conversion using native microbial consortia. The native consortia were obtained by batch enrichment method applied on oil-polluted soil samples from oil refineries of Iran. The bioconversion experiments were conducted with 20% and 40% (v/v) of the heavy cut as the sole carbon source and 10% (v/v) of the consortia broth in 250 ml flasks containing a mineral medium. The samples kept at 30°C stirring at 120 rpm for one week. The biotreated hydrocarbons were then separated and analyzed for determination of saturate, aromatic and resin fractions using column chromatography and gravimetric measurements. The results showed that the amounts of saturates increased by 6% to 92% while the resins decreased by 10% to 70% in most cases, compared to the blank. The GC-Mass analysis of the saturate fractions also revealed an increase in the cyclic and branched alkanes and a decrease in the S-containing and N-containing compounds.
    Keywords: Biological upgrading, Biocracking, Bioconversion, Petroleum, Heavy oil cut
  • Evaluation and modeling of radiation and noise pollution in the north of the Persian Gulf (Case study: South Pars gas platforms)
    Mohammad Mardani, Mohsen Nowrouzi, Hajar Abyar Pages 229-238

    Gas flaring in the petrochemical industries is an important issue due to the significant economic value of the emitted gases and the detrimental effects on the environment and workers’ health through gas combustion. Iran has the second largest gas reservoir in the world, with an extensive facility for gas exploitation in the Persian Gulf, indicating its significant role in the environmental conditions of the Persian Gulf. Therefore, this investigation, for the first time, endeavored to evaluate the design of offshore flares and model the amount of produced radiation and noise in the South Pars gas platforms using Flaresim software. The field data were obtained from Phase 7 of the South Pars platform. The results indicated that the amount of radiation from the flare flame in the surrounding area and the receptor points was less than the American Petroleum Institute (API) standard 521 regarding the stack length of 305 ft. The estimated values were 286 (0.9021 kW/m2 ) and 283.9 btu/h/ft2 (0.8955 kW/m2 ) in the base-flare and helideck areas, respectively. Moreover, the noise level in the receptors was less than the standard of the Occupational Health Organization of Iran. The current investigation can provide a practical framework to assess the compatibility of flare systems with environmental standards towards achieving sustainable development.

    Keywords: Persian Gulf, South Pars, Flare, Radiation, Noise Pollution
  • Manali Date, Dipika Jaspal * Pages 239-253

    The foibles in extant wastewater treatment technologies release untreated nitrate and ammonia containing compounds into different potable water sources. The toxicity and fatal effects of entrained nitrate and ammonia produce lethal health consequences upon being consumed. Novel methods obtained by combining light, electrical, and chemical energy have opened new frontiers of pronounced efficiency and reduced demerits. These methods lead to the destruction of nitrate instead of just removing it by adsorption on the surface of another material. Photochemical (PC) and electrochemical (EC) reactions offer a vast scope for degrading harmful ammonia and nitrates from wastewater. The catalyzed form of these processes has been found to be meritorious over non-catalyzed techniques due to several advantages like improved efficiency, lower energy input, lower reaction time, and product selectivity towards N2 gas over nitrate and nitrite. This paper presents a review of significant research that has been performed using PC, EC, and photoelectrochemical (PEC) to remove ammonia and nitrate from wastewater. Not much research is available on the combined and simultaneous use of PC and EC oxidation and reduction processes which have immense potential as future methodologies for treating municipal and industrial wastewater to remove these toxic inorganic nitrogenous compounds. High ammonia and nitrate removal efficiencies at the laboratory scale have been reported using specific combinations of catalysts, pH, cell composition, electrodes, electrical input, and reaction time by electrochemical denitrification. However, they lack practical viability. Catalyzed photochemical processes are successful in removing ammonia and nitrate to a large extent and are practically viable if carried out using natural sunlight. Combined PC and EC, i.e., PEC oxidation and reduction processes, eliminate the occurrence of toxic intermediates and give about 90 % to 98 % conversion of ammonia and nitrate in the form of nitrogen gas.

    Keywords: Photochemical Oxidation, Reduction, Electrochemical Oxidation, catalysed, catalyst loaded nanofiber