scholarly journals Degradation of phenol using US/Periodate/nZVI system from aqueous solutions

2019 ◽  
Keyword(s):  
Free Radicals ◽  
Aqueous Solutions ◽  
Removal Efficiency ◽  
Batch Reactor ◽  
Experimental Tests ◽  
Zero Valent Iron ◽  
Acidic Ph ◽  
Alkaline Ph ◽  
Iron Nanoparticle ◽  
Ultrasound System

<p>In the present work, the degradation of phenol from aqueous solutions was investigated using periodate/zero valent iron nanoparticle (nZVI) in the presence of ultrasound at a batch reactor. The Experimental tests were carried out using pre-designated amounts of nZVI, periodate, and pH ranging from 1-7 mM, 0.5-5 mM, 3-11 respectively. During the all experimental tests the ultrasonic reactor was operated at a fix frequency (40 kHz), temperature (33±1) and power (350 W). The results of nZVI/periodate/ultrasound system on degradation of phenol showed that the removal efficiency was frankly affected by the amount of produced free radicals to initiate the oxidative decomposition of phenol. As, with enhancing the nZVI loading to 3 mM and periodate concentration to 3 mM, the removal efficiency of phenol was increased. Besides, the acidic pH (pH=3) was found to be more effective than neutral and alkaline pH in degradation of phenol.</p>

scholarly journals Evaluate the effectiveness of the UV/ persulfate process to remove catechol from solution aqueous

2021 ◽  
Keyword(s):  
Data Analysis ◽  
Aqueous Solutions ◽  
Uv Radiation ◽  
Removal Efficiency ◽  
Design Of Experiment ◽  
Contact Time ◽  
Batch Reactor ◽  
Acidic Ph ◽  
Optimum Conditions ◽  
Optimum Ph

<p>Catechol is used as an antioxidant, fungicide, and polymerization inhibitors in a variety of industries such as petrochemical. Catechol must be removed from effluents before it enters to environment. This study aimed to investigate combined UV radiation and persulfate process in removal of catechol from aqueous solutions. All experiments were performed in a batch reactor. Data analysis were done with Design of Experiment (DoE) software. The effects of various variables such as pH, initial persulfate concentration, and initial Catechol concentration were investigated. The findings indicated with increases in persulfate concentration and decrease in catechol concentrations, the removal efficiency increased. Acidic pH and UV radiation were the leading factors in removal of catechol. The optimum pH, persulfate concentration, and catechol concentration were obtained 7, 0.04 M, and 100 mg l-1, respectively. More removes of catechol was achieved in optimum conditions within contact time of 60 min. The synergic effects of UV and persulfate radical were about 88%. Approximately 60% of catechol was mineralized within contact time of 60 min. Persulfate radicals resulting from UV/S2O82- were the main effective oxidants in removal and mineralization of catechol. Owing to high removal efficiency of persulfate compounds which are, also, abundant and inexpensive, these can be applied in removal of persistent organic pollutants from aqueous solutions.</p>

Impacts of variable pH on stability and nutrient removal efficiency of aerobic granular sludge

2015 ◽  
Vol 73 (1) ◽  
pp. 60-68 ◽  
Author(s):  
Monireh Lashkarizadeh ◽  
Giulio Munz ◽  
Jan A. Oleszkiewicz
Keyword(s):  
Removal Efficiency ◽  
Nutrient Removal ◽  
Phosphorus Removal ◽  
Granular Sludge ◽  
Aerobic Granular Sludge ◽  
Acidic Ph ◽  
Alkaline Ph ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Ph Shock

The impact of pH variation on aerobic granular sludge stability and performance was investigated. A 9-day alkaline (pH = 9) and acidic (pH = 6) pH shocks were imposed on mature granules with simultaneous chemical oxygen demand (COD), nitrogen and phosphorus removal. The imposed alkaline pH shock (pH 9) reduced nitrogen and phosphorus removal efficiency from 88% and 98% to 66% and 50%, respectively, with no further recovery. However, acidic pH shock (pH 6) did not have a major impact on nutrient removal and the removal efficiencies recovered to their initial values after 3 days of operation under the new pH condition. Operating the reactors under alkaline pH induced granules breakage and resulted in an increased solids concentration in the effluent and a significant decrease in the size of the bio-particles, while acidic pH did not have significant impacts on granules stability. Changes in chemical structure and composition of extracellular polymeric substances (EPS) matrix were suggested as the main factors inducing granules instability under high pH.

scholarly journals The Removal of Amoxicillin with Zno Nanoparticles in Combination with US-H2O2 Advanced Oxidation Processes from Aqueous Solutions

2019 ◽  
Author(s):  
Somayeh Rahdar ◽  
Shahin Ahmadi
Keyword(s):  
Aqueous Solutions ◽  
Removal Efficiency ◽  
Contact Time ◽  
Advanced Oxidation Processes ◽  
Batch Reactor ◽  
Advanced Oxidation ◽  
Optimal Conditions ◽  
Zno Nps ◽  
Oxidation Processes ◽  
The Us

Background and purpose: The aim of this study was to evaluate the efficiency of zinc oxidenanoparticles (ZnO NPs) in combination with US-H2O2 advanced oxidation processes (AOPs) for the removal of antibiotic amoxicillin (AMO) from aquatic environment.Materials and Methods: This experimental study was conducted in a batch reactor system. The effect of the parameters, such as pH (3-8), the dose of nanoparticles (0.01-0.08 g/L), reaction time (10-100 min), the initial concentration of the AMO (150-250 mg/L) and H2O2 (0.1 – 5Mol/L) on the removal efficiency were studied in ultrasonic reactor. The residual AMO concentrations were measured at 190 nm using a UV/Vis spectrophotometer.Results: The results showed that the US-H2O2 advanced oxidation processes using ZnO NPs can effectively lead to the removal of AMO from the wastewater. The optimal conditions for this process were pH 3, 0.1 M of H2O2 and the dose ZnO NPs 0.05 g/L and time of 60 minutes. In the current study, it was found that the removal efficiency dropped with the increasing concentrations of AMO. Under optimal conditions with 150 mg/L of AMO and contact time of 60 min, the efficiency removal was also equal to 92.47%.Conclusion: The results of this study showed that AOP was a very effective method that can be used for the removal of AMO antibiotic from aqueous solutions.

Treatment characteristics and effects of nanoparticle zero-valent iron (nZVI) powder on nitrogen removal efficiency for sewage treatment

2014 ◽  
Vol 49 (3) ◽  
pp. 273-284 ◽  
Author(s):  
Mi-Sug Kim ◽  
Dong-Heui Kwak
Keyword(s):  
Removal Efficiency ◽  
Nitrogen Removal ◽  
Batch Reactor ◽  
Nitrate Removal ◽  
Sewage Treatment ◽  
Synthetic Zeolite ◽  
Zero Valent Iron ◽  
Silica Sand ◽  
Experimental Conditions ◽  
N Removal

This study aims at estimating nanoparticle typed zero-valent iron (nZVI) process as an advanced nitrogen removal technique. To focus on investigating characteristics and effects of nZVI on nitrogen removal for sewage treatment, batch reactor experiments were conducted to reduce excessive nitrate nitrogen (NO3-N). To improve NO3-N removal efficiency and to find a supporter or alternative of nZVI, silica sand, synthetic zeolite, and a mixture of silica sand, synthetic zeolite, and nZVI were used in the experiments. As a result of this study, the chemical denitrification by nZVI attracted on the magnet surface may be useful for total nitrogen removal in conventional sewage and wastewater treatment plants under the optimal conditions, and application of silica sand also is an excellent adsorbent or media for N-component removal and a supporter as well. This study concludes the end product in this study may be nitrogen gas (N2) through Fe0 reaction with O2 and NO3− in aerobic nZVI (Fe0)–H2O system. Future study is required to examine the competition of nZVI between nitrate and many other compounds depending upon various experimental conditions for improving the nitrate removal efficiency and impeding the ammonium generation.

scholarly journals REGULARITIES OF THE INTERACTION OF POLYSTYRENE SULPHOIC ACID WITH COBALT IONS IN AQUEOUS SOLUTIONS

2021 ◽  
pp. 61-65
Author(s):  
D. M. Vishnivetskaya ◽  
A. S. Sokolova ◽  
A. S. Ozerin ◽  
A. E. Mikhailyuk ◽  
F. S. Radchenko ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Sodium Salt ◽  
Sulfonic Acid ◽  
Acidic Ph ◽  
Alkaline Ph ◽  
Cobalt Sulfate ◽  
Cobalt Ions ◽  
Methods Of Analysis ◽  
Polystyrene Sulfonic Acid

Mixtures of solutions of sodium salt of polystyrene sulfonic acid and cobalt sulfate were investigated by spectrophotometric and conductometric methods of analysis. It was shown that polystyrene sulfonic acid macromolecules do not form complexes with cobalt ions in both acidic (pH = 2) and alkaline (pH = 9) media.

scholarly journals Efficient Sequestration of Hexavalent Chromium by Graphene-Based Nanoscale Zero-Valent Iron Composite Coupled with Ultrasonic Pretreatment

2021 ◽  
Vol 18 (11) ◽  
pp. 5921
Author(s):  
Haiyan Song ◽  
Wei Liu ◽  
Fansheng Meng ◽  
Qi Yang ◽  
Niandong Guo
Keyword(s):  
Aqueous Solution ◽  
Removal Efficiency ◽  
Inhibitory Effect ◽  
Ultrasonic Cavitation ◽  
Zero Valent Iron ◽  
Ultrasonic Pretreatment ◽  
Nanoscale Zero Valent Iron ◽  
Passivation Layers ◽  
Initial Ph ◽  
Two Phases

Nanoscale zero-valent iron (nZVI) has attracted considerable attention for its potential to sequestrate and immobilize heavy metals such as Cr(VI) from an aqueous solution. However, nZVI can be easily oxidized and agglomerate, which strongly affects the removal efficiency. In this study, graphene-based nZVI (nZVI/rGO) composites coupled with ultrasonic (US) pretreatment were studied to solve the above problems and conduct the experiments of Cr(VI) removal from an aqueous solution. SEM-EDS, BET, XRD, and XPS were performed to analyze the morphology and structures of the composites. The findings showed that the removal efficiency of Cr(VI) in 30 min was increased from 45.84% on nZVI to 78.01% on nZVI/rGO and the removal process performed coupled with ultrasonic pretreatment could greatly shorten the reaction time to 15 min. Influencing factors such as the initial pH, temperature, initial Cr(VI) concentration, and co-existing anions were studied. The results showed that the initial pH was a principal factor. The presence of HPO42−, NO3−, and Cl− had a strong inhibitory effect on this process, while the presence of SO42− promoted the reactivity of nZVI/rGO. Combined with the above results, the process of Cr(VI) removal in US-nZVI/rGO system consisted of two phases: (1) The initial stage is dominated by solution reaction. Cr(VI) was reduced in the solution by Fe2+ caused by ultrasonic cavitation. (2) In the following processes, adsorption, reduction, and coprecipitation coexisted. The addition of rGO enhanced electron transportability weakened the influence of passivation layers and improved the dispersion of nZVI particles. Ultrasonic cavitation caused pores and corrosion at the passivation layers and fresh Fe0 core was exposed, which improved the reactivity of the composites.

scholarly journals Carbothermal Synthesis of Ni/Fe Bimetallic Nanoparticles Embedded into Graphitized Carbon for Efficient Removal of Chlorophenol

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1417
Author(s):  
Min Zhuang ◽  
Wen Shi ◽  
Hui Wang ◽  
Liqiang Cui ◽  
Guixiang Quan ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Surface Passivation ◽  
Bimetallic Nanoparticles ◽  
Zero Valent Iron ◽  
Molar Ratio ◽  
Particle Sizes ◽  
Iron Corrosion ◽  
Graphitized Carbon ◽  
Nanoscale Zero Valent Iron ◽  
Iron Nickel

The reactivity of nanoscale zero-valent iron is limited by surface passivation and particle agglomeration. Here, Ni/Fe bimetallic nanoparticles embedded into graphitized carbon (NiFe@GC) were prepared from Ni/Fe bimetallic complex through a carbothermal reduction treatment. The Ni/Fe nanoparticles were uniformly distributed in the GC matrix with controllable particle sizes, and NiFe@GC exhibited a larger specific surface area than unsupported nanoscale zero-valent iron/nickel (FeNi NPs). The XRD results revealed that Ni/Fe bimetallic nanoparticles embedded into graphitized carbon were protected from oxidization. The NiFe@GC performed excellently in 2,4,6-trichlorophenol (TCP) removal from an aqueous solution. The removal efficiency of TCP for NiFe@GC-50 was more than twice that of FeNi nanoparticles, and the removal efficiency of TCP increased from 78.5% to 94.1% when the Ni/Fe molar ratio increased from 0 to 50%. The removal efficiency of TCP by NiFe@GC-50 can maintain 76.8% after 10 days of aging, much higher than that of FeNi NPs (29.6%). The higher performance of NiFe@GC should be ascribed to the significant synergistic effect of the combination of NiFe bimetallic nanoparticles and GC. In the presence of Ni, atomic H* generated by zero-valent iron corrosion can accelerate TCP removal. The GC coated on the surface of Ni/Fe bimetallic nanoparticles can protect them from oxidation and deactivation.

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