23 research outputs found
Application of electrochemical coagulation process with iron and aluminum modified by zinc oxide nanoparticles by cyclic voltammetry in removal of reactive blue 19 dye
No full textIn recent years, the processes used in wastewater treatment have received significant advances in various fields, including the electrochemical coagulation process as a significant innovation in the water and wastewater industry. The application of electrochemical technologies in the water and wastewater industry is very diverse. This technique has been applied in various situations and industries to remove a wide range of pollutants. Reactive dyes are a group of dyes widely used for dyeing cellulose fibers, especially linen fabrics used. The anthracavon dyes after the azo dyes are the second group of textile dyes. Reactive blue 19 is the anthraquinone dye in terms of color factor. Various methods have been used to treat this type of wastewater, including various physical and chemical treatment methods (such as filtration, settling, ozonation), each with its own disadvantages such as: low efficiency, high cost, high time and cause secondary pollution. Accordingly, electrochemical coagulation treatment to remove contamination from dye wastewater due to its high efficiency is studied. The purpose of this study was to evaluate the electrochemical removal of reactive blue 19 dye using iron and aluminum electrodes. The dye concentration was also considered at 200 mg/L for all stages and all experiments were performed at ambient temperature. Main parameters such as electrode spacing, type of electrode arrangement, anode electrode (iron and aluminum), coating of aluminum electrode with ZnO nanoparticles by physical evaporation layer-addressing method and evaluation of coating performance by scanning speed cyclic voltammetry system and different voltage ranges were used. In the optimum condition in the removal of synthetic contaminants including electrode distance of 3 cm, parallel monopolar electrode arrangement, use of iron anode electrode pair and aluminum cathode with ZnO nanoparticle coating, retention time equals to 32.66 minutes, current density 14.34 mA/cm2 and initial pH of 4, the percentage of dye wastwater was 93.8 percent. The use of zinc oxide nanoparticles coated by the physical evaporation layering method also improved the 173.12% electrical current
Reaction Kinetics of Aniline Synthetic Wastewater Treatment by Moving Bed Biofilm Reactor
No full text"n "nBackground and Objectives: Experiments were conducted to investigate the behavior of Moving Bed Biofilm Reactor (MBBR) as a novel aerobic process for treatment of aniline synthetic wastewater as a hard biodegradable compound is commonly used in number of industrial processes. The objective of this paper is evaluation of MBBR in different conditions for treatment of aniline and determination of reaction kinetics."nMaterials and Methods: In the MBBRs, different carriers are used to maximize the active biofilm surface area in the reactors. In this study, the reactor was filled with Light Expanded Clay Aggregate (LECA) as carriers. Evaluation of the reactor efficiency was done at different retention time of 8, 24, 48 and 72 hours with an influent COD from 100 to 3500 mg/L (filling ratio of 50%). After obtaining removal efficiencies, effluent concentration of aniline was measured by adsorption spectrum and maladaptive municipal wastewater treatment plant sludge in batch conditions for confidence of aniline biodegradation and its adsorption to the sludge mass. "nResults:The maximum obtained removal efficiencies were 91% (influent COD=2000 mg/L) after 72 hours. Biodegradation of aniline in MBBR has been also approved by NMR spectrum tests. Finally experimental data has indicated that Grau second order model and Stover-Kincannon were the best models to describe substrate loading removal rate for aniline."nConclusion:biological treatment of aniline wastewater compared to other researchers methods
Photocatalytic treatment of real oil refinery wastewater using TiO2/Ag-doped nanoparticles
No full textIn this study, the removal and degradation of organic pollutants from real oil refinery effluent was investigated using a synthesized TiO2/Ag photocatalyst fixed on lightweight concrete plates. Petroleum compounds are a set of hydrocarbons some of which are stable, long-term decomposing, poisonous and even carcinogen for human. One of the attractive wastewater treatment techniques is photocatalytic purification and this process has the potential to mineralize all organic and inorganic compounds found in petroleum impregnated processes and convert them into biodegradable and biodegradable compounds. Characterization of synthetic photocatalysts was done using X-Ray Diffraction (XRD) Fourier Transform Infrared Spectroscopy (FT-IR) techniques, Scanning Electron Microscopy (SEM) with EDX analysis, and Nitrogen Adsorption and Desorption (BET). The photocatalytic pilot consisted of three 20×20×5cm lightweight concrete plates coated the nanoparticles on the concrete surface and powered by 36-watt UVA lamps. SEM experiment results showed relatively uniform TiO2/Ag coating on lightweight concrete surface. The synthesized photocatalyst XRD pattern showed the successful synthesis of Ag crystals in the nanocomposite structure. BET results showed that when TiO2/Ag was synthesized, the cavities became mesoporous. Investigation of the effect of pH on the system efficiency in the range of 3 to 12 showed that at pH 4.5, the removal efficiency reached its highest level. The effect of mass loading of TiO2/Ag nanoparticles on the concrete plates showed that the highest removal efficiency in mass loading was 15 gr/m2. To study the rate of COD removal under sun light, the reactor was transferred to the yard in Kharazmi University in Tehran. To obtain results, the experiment was performed three times in both states of using TiO2 and TiO2/Ag under optimum conditions. The rate of COD removal under sunlight for 8 hours and the use of UV-A lamps for TiO2/Ag photocatalysts were 51.8% and 76.3%, respectively. The results showed that the synthetic photocatalyst was capable of treating real wastewater using UV rays
Biodegradation Of Aromatic Amine Compounds Using Moving Bed Biofilm Reactors
No full textThree moving bed biofilm reactors were used to treat synthesized
wastewater of aromatic amine compounds including aniline,
para-diaminobenzene and para-aminophenol that are found in many
industrial wastewaters. The reactors with cylindrical shape had an
internal diameter and an effective depth of 10 and 60 cm, respectively.
The reactors were filled with light expanded clay aggregate as carriers
and operated in an aerobic batch and continuous conditions. Evaluation
of the reactors' efficiency was done at different retention time of 8,
24, 48 and 72 h with an influent COD from 100 to 3500 mg/L (filling
ratio of 50%). The maximum obtained removal efficiencies were 90%
(influent COD=2000 mg/L), 87% (influent COD=1000 mg/L) and 75%
(influent COD=750 mg/L) for aniline, para-diaminobenzene and
paraaminophenol, respectively. In the study of decrease in filling
ratio from 50 to 30 percent, 6% decrease for both para-diaminobenzene
and para-aminophenol and 7% increase for aniline degradation were
obtained. The removal efficiency was decreased to about 10% after 15
days of continuous loading for each of the above three substrates. In
the shock loading test, initially the COD removal rate was decreased in
all reactors, but after about 10 days, it has been approached to the
previous values. Finally, biodegradability of aromatic amines has been
proved by nuclear magnetic resonance system
Eco-friendly biodiesel production from olive oil waste using solar energy
No full textThis study was carried out to produce biodiesel from olive oil waste by transesterification reaction. Several important reaction variables (the weight ratio of oil to methanol, the temperature, and reaction time) were evaluated to obtain a high quality of biodiesel fuel that meets authentic standards. Solar energy was applied for the transesterification reaction and electricity generated by photovoltaic panels was used to power a motor for mixing the reaction solution
IMPROVING THE PRODUCTION PROCESS OF BIODIESEL FROM WASTE OIL BY TIO2 CATALYTIC NANOPARTICLES COMPARED WITH CONVENTIONAL CATALYST, SODIUM
No full textDue to a huge increase in world energy consumption, the limited traditional fossil energy resources, and increased environmental concerns, a requirement for alternative energy sources has been paid great attention in recent years. Biodiesel is known as a nontoxic, renewable and environmental-friendly biodegradable fuel that is free from sulfur and aromatic compounds. The biodiesel production by transesterification of vegetable oils has the potential to solve the above problems and concerns. Nanocatalysts are considered as important material in chemical processes, energy production and energy savings, and prevent environmental pollution. In this study, the characteristics and performance of TiO2 nanoparticles (TNPs) and one commonly used catalyst for
alkaline-catalyzed transesterification, i.e., sodium hydroxide, were evaluated using waste olive oil. The present method affords nontoxic and non-corrosive medium, high yield of biodiesel, clean reaction and simple experimental and isolation procedures. The catalyst can be recycled by simple filtration and reused without any significant reduction in its activity. The process variables
that influence the transesterification of triglycerides, such as volume ratio of methanol to waste olive oil, type and loading of catalyst, reaction time and reaction temperature, were investigated. High catalysis activity and a much more specific surface TNPs were found to be more superior to sodium hydroxide under the same conditions. The results showed that TNPs as catalyst can improve the biodiesel production up to 87.8\% in the same condition in which the efficiency is 76.4\% for sodium hydroxide as a homogeneous catalyst. The effect of biodiesel/diesel blend fuels on engine exhaust emissions in a Robin engine was evaluated. The testing results show that the B20 blend fuel (including 20\% and 80\% v/v biodiesel and diesel fuel, respectively) reduced (HC) and carbon monoxide (CO) emissions to 28.9 and 20.6\% compared to the petroleum diesel fuel, respectively. In addition, in this study, the effective use of biodiesel to reduce air pollutant emissions was approved, although a slight increase in
nitrogen oxides emissions than pure diesel fuel was observed that quite what was expected due to increasing combustion temperature
Biological removal of diazinon in a moving bed biofilm reactor – process optimization with central composite design
No full textCrumpling for energy: modeling generated power from the crumpling of polymer piezoelectric foils for wearable electronics
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