Photodegradation of reactive blue 19 dye using magnetic nanophotocatalyst α-Fe2O3/WO3: A comparison study of α-Fe2O3/WO3 and WO3/NaOH

The photocatalytic degradation of reactive blue 19 (RB19) dye was investigated in a slurry system using ultraviolet (UV) and light-emitting diode (LED) lamps as light sources and using magnetic tungsten trioxide nanophotocatalysts (α-Fe2O3/WO3 and WO3/NaOH) as photocatalysts. The effects of different parameters including irradiation time, initial concentration of RB19, nanophotocatalyst dosage, and pH were examined. The magnetic nanophotocatalysts were also characterized with different methods including scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), X-ray diffraction (XRD), photoluminescence (PL), differential reflectance spectroscopy (DRS), Fourier transform infrared spectroscopy (FTIR), and vibrating sample magnetometry (VSM). The XRD and FTIR analyses confirmed the presence of tungsten trioxide on the iron oxide nanoparticles. The VSM analysis confirmed the magnetic ability of the new synthesized nanophotocatalyst α-Fe2O3/WO3 with 39.6 emu/g of saturation magnetization. The reactor performance showed considerable improvement in the α-Fe2O3-modified nanophotocatalyst. The impact of visible light was specifically investigated, and it was compared with UV-C light under the same experimental conditions. The reusability of the magnetic nanophotocatalyst α-Fe2O3/WO3 was tested during six cycles, and the magnetic materials showed an excellent removal efficiency after six cycles, with just a 7% decline

A Study for Water Purification Using Reverse Osmosis Membrane Modified with Carbon Nanotube

Water desalination systems is among the methods used to produce potable water to be used for domestic, agricultural and industrial applications.  Reverse osmosis is a common methods  employed for desalination facilities, mainly because of its low energy consumption, and high efficiency for permeate production. The main aim of this research is to use nanocomposite containing carbon nanotubes to improve membrane wall performance. in addition, the increase in the flux as a result of decreased clogging surface on the membrane was also studied.  To accomplish the objective of the study, the synthesized polyamid reverse osmosis nanocomposite membrane were used for purification of brackish water with the characteristic of having the electroconductivity of 4000 µs/cm. The modified raw-multi walled carbon nanotubes membrane was embedded through polymerization method in order to increase porosities and hydrophilicity. Analysis of Contact angle, SEM, FTIR and AFM were done for recognizing the compounds which were created on the surface of membranes and membranes hydrophilicity. Three sets of samples were prepared for testing in the membrane cell synthesis analysis. Water flux and rejection rates were assessed every 30 minutes. Results of this study showed that the membranes have soft hydrophil surfaces and by increasing nanocomposite concentrations with specified measure, the water flux increased up to 30.8 L/m2h which was noticeable compared to the simple polyamide membranes. Our results also showed that fouling reduced considerably and the clogging condition was reduced by nanocomposite membranes, and the rejection rate was higher than 97 percent for all synthesized membranes with pyrrol

Application of Mathematical Models for Determination of Microorganisms Growth Rate Kinetic Coefficients for Wastewater Treatment Plant Evaluation

Background& Objective: Determination of microorganisms growth kinetic constant is one of the most important parameters for evaluation of municipal and industrial wastewater treatment plants efficiency. Monod Equation and activated sludge models (ASM1) are one of the most important relationships for design of activated sludge biological process. Materials and Methods: Data obtained using a laboratory pilot in accordance with the amount of aeration, temperature and pH and the concentration of the feed inlet to the Ekbatan wastewater treatment plantin Tehran. Changes in microbial growth by measuring MLVSS and COD changes of input substrate in the range of 50-500 mg/L was investigated. Results: The results of the ASM1 model for kinetic coefficients of Ks were determined as 31.2 gCOD.m-3, µH as 3.9 day-1, bH as 0.077 day-1 and YH as 0.51 gCOD XH (gCOD SS)-1. The difference between ASM1 and Common equations in activated sludge processes was 7.6%, 9.2%, 9.4% and 6.9% for Ks, µH, bH and YH, respectively. Conclusion: Evaluation of Y, kd, k0 and Ks parameters in operation of Ekbatan wastewater treatment plant showed that ASM1 model could well determine the coefficients and therefore the conditions of biological treatment is appropriate

UV-light-responsive Ag/TiO2/PVA nanocomposite for photocatalytic degradation of Cr, Ni, Zn, and Cu heavy metal ions

Abstract The rapid growth of industrialization has led to the uncontrolled pollution of the environment, and rapid action is needed. This study synthesized Ag/TiO2/polyvinyl alcohol (PVA) nano photocatalyst for promising light-derived photocatalytic removal of heavy metal ions. The design of experiment (DOE) was used to study the effect of important factors (pH, reaction time, and photocatalyst dosage) to maximize the final performance of the photocatalyst. In the optimized condition, the Ag/TiO2/PVA nano-photocatalyst removed more than 94% of Cr6+ in 180 min, and the efficiency was more than 70% for Cu2+, Zn2+, and Ni2+ metal ions. The adsorption of the heavy metal ions on the photocatalyst was described well with the Langmuir isotherm, while the pseudo-second-order linear kinetic model fitted with the experimental data. The nano-photocatalyst's stability was confirmed after maintaining its performance for five successive runs. The enhanced photocatalytic activity for the heavy metal ions removal can be attributed to the presence of metallic silver nanoparticles (electron transfer and plasmonic fields mechanisms) and PVA, which delayed the recombination of electron–hole. The synthesized ternary Ag/TiO2/PVA nano-photocatalyst showed promising performance for the elimination of heavy metal ions and can be used for environmental remediation purposes

Treatment of Wastewater Containing Aniline Using a Moving Bed Biofilm Reactor (MBBR)

In this research, the capability of the moving bed biofilm reactor (MBBR) for the treatment of aniline wastewater has been investigated. This compound is found in effluents from chemical, dye, pigment, herbicide, pharmaceutical, plastic, and paint industries. The moving bed biofilm reactor was developed to adopt the best features of the activated sludge process as well as those of the biofilter processes. In this study, a cylindrical moving bed biofilm reactor with an approximate capacity of 5 liters was used. The effects of LECA (Light Expanded Clay Aggregate) filling ratio and retention times (RT) of 8, 24, 48, and 72 hr were investigated on removal efficiency for different influent COD values. The best removal efficiency of 91% was obtained for a COD level of 2000 mg/L after 72 hour. Other experiments were conducted to evaluate the removal efficiency of the reactor under a decreased carrier volume of 30% and under continuous loading. NMR test results confirmed the capability of the reactor in the biodegradation of aniline. The capability of the reactor was also evaluated by feeding an organic shock that resulted in satisfactory performance of MBBR. The results showed that Grau and Stover-Kincannon were the best models to describe the biological kinetic data in this study

Treatment of Synthetic Wastewater Containing of Cd(II) Using Novel Magnetic EDTA/Chitosan/TiO2 Nanocomposite

Background: Cadmium, as a heavy metal, has received considerable attention due to its high toxicity, causing excessive damage to health and the biomagnification effects on ecology. In present study, a facile and economic approach has been described for preparing a novel magnetic EDTA/Chitosan/TiO2 (MECT) nanocomposite to remove a wide range of pollutants, especially Cd(ІІ) ions, from aqueous solution. Methods: In this method, not only EDTA has a cheap and environmentally friendly cross-linker function, embeds Fe3O4 nanoparticles in chitosan surface, but also participates in the chelating process of metal ions, caused by functional groups. The morphology, structure, and property of the MECT were characterized by FE-SEM, EDX, and XRD techniques and the effect of different parameters including pH, contact time, and initial cadmium concentration were evaluated. Results: The results represented that MECT nanoparticles with an average diameter less than 40 nm had the best performance in adsorption of Cd(II) at optimum pH values of 5-6 and contact time of 120 min. Moreover, Langmuir adsorption isotherm is the best fit for the experimental data, in which maximum capacity of Cd(II) adsorption has been achieved 211.416 mg g-1. Finally, reusability of the nanocomposite was measured using Na2EDTA as an elution agent and regeneration efficiency of MECT was observed more than 90% in five successive sorption-desorption cycles. Conclusions: Thus, magnetic MECT nanocomposite as an environmentally friendly, economical, and recyclable adsorbent has a great potential to develop the industry of water and wastewater treatment. &nbsp

A Comparative Study On The Action Potential Simulation (APS) Therapy And The Routine Physiotherapy Protocol In Knee Osteoarthritisin Elderly People

Background and Aim: Knee osteoarthritis is the most common cause for which the elderly people refere to physiotherapy outpatient clinics. This study aimed to investigate the effects of the Action Potential Stimulation (APS) Therapy and the routine physiotherapy (PT) protocol on relieving pain and swelling as well as the duration of the relief period in patients with knee osteoarthritis. Materials and Methods: 69 patients (62 females & 7 males) with knee osteoarthritis were recruited in this study. The subjects were divided into two groups including APS Therapy (n=37, mean age: 55±13 years old) and the routine PT protocol (n=32, mean age: 61±14 years old) groups. A 10-session treatment period was carried out for each group; and their pain and swelling were measured at the first, fifth and tenth sessions and also one-month after the last session (follow up). The swelling was measured using measuring the circumference of the knee on the patella, 5 Cm above and 5 Cm below the patella. The routine PT protocol consisted of hot pack, ultrasound, TENS and exercise; and the APS therapy protocol included hot pack, APS Therapy and the same exercise. During the follow up, 50 out of 61 subjects were called on the phone and any pain changes were recorded.Results: In terms of swelling, the results showed significant reduction just on the patella only in the APS Therapy group (P<0.05). Visual Analogue Pain Scale (VAPS) indicated a significant pain reduction in both groups. However, the APS Therapy group showed significantly pain reduction at the end of sessions five, ten and the follow up session (P<0.05). It was also revealed that while routine PT subjects showed no significant pain changes between the tenth and the follow up session, a gradual pain reduction was seen in the APS therapy group during this period (P<0.05). A gradual dosage reduction was recorded only in the APS therapy group, indicating a slight correlation with pain reduction (r=0.4).Conclusion: The findings of this study showed significantly better results following the use of APS therapy protocol relative to the routine PT protocol in patients with knee osteoarthritis and hence are recommended to these patients

Application of TiO2 nanoparticles for eco-friendly biodiesel production from waste olive oil

An environmentally benign, simple, and efficient process has been developed for biodiesel production from waste olive oil in the presence of a catalytic amount of TiO2 nanoparticles at 120°C with a conversion of 91.2% within 4 h. The present method affords nontoxic and noncorrosive 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

Dataset of producing and curing concrete using domestic treated wastewater

We tested the setting time of cement, slump and compressive and tensile strength of 54 triplicate cubic samples and 9 cylindrical samples of concrete with and without a Super plasticizer admixture. We produced concrete samples made with drinking water and treated domestic wastewater containing 300, 400 kg/m3 of cement before chlorination and then cured concrete samples made with drinking water and treated wastewater. Second, concrete samples made with 350 kg/m3 of cement with a Superplasticizer admixture made with drinking water and treated wastewater and then cured with treated wastewater. The compressive strength of all the concrete samples made with treated wastewater had a high coefficient of determination with the control concrete samples. A 28-day tensile strength of all the samples was 96–100% of the tensile strength of the control samples and the setting time was reduced by 30 min which was consistent with a ASTMC191 standard. All samples produced and cured with treated waste water did not have a significant effect on water absorption, slump and surface electrical resistivity tests. However, compressive strength at 21 days of concrete samples using 300 kg/m3 of cement in rapid freezing and thawing conditions was about 11% lower than concrete samples made with drinking water