Degradation of Orange II in aqueous solution by a novel electro/Fe3O4 process

2013 ◽  
Vol 68 (11) ◽  
pp. 2441-2447 ◽  
Author(s):  
Heng Lin ◽  
Liwei Hou ◽  
Hui Zhang
Keyword(s):  
Aqueous Solution ◽  
Current Density ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Reactor ◽  
Orange Ii ◽  
Toc Removal ◽  
Anode Oxidation ◽  
Stainless Steel Cathode ◽  
Before And After ◽  
Initial Ph

The removal of Orange II in aqueous solution by Fe3O4 enhanced anode oxidation (EC/Fe3O4 process) was performed in an electrochemical reactor. The process involved the use of a dimensionally stable anode and a stainless steel cathode. Fe3O4 was performed as particle electrodes to increase mass transfer coefficient and reduce energy consumption. Various parameters were investigated to optimize the process, including initial pH, Fe3O4 dosage and current density. The results indicated that the decolorization of Orange II followed pseudo first-order kinetics. The decolorization was favorable in acidic media than in neutral or alkaline solution, while it increased with the Fe3O4 dosage and current density. The total organic carbon (TOC) removal efficiency was 33.2% after 120 min reaction. The X-ray photoelectron spectroscopy was applied to investigate the surface properties of Fe3O4 before and after reaction.

scholarly journals Adsorption of Lead (II) from Aqueous Solution with High Efficiency by Hydrothermal Biochar Derived from Honey

2020 ◽  
Vol 17 (10) ◽  
pp. 3441 ◽  
Author(s):  
Bo Wang ◽  
Jie Yu ◽  
Hui Liao ◽  
Wenkun Zhu ◽  
Pingping Ding ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Photoelectron Spectroscopy ◽  
High Efficiency ◽  
Raw Material ◽  
Before And After ◽  
Initial Ph ◽  
Carboxylic Groups ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order ◽  
Natural Honey

A novel natural honey hydrothermal biochar (HHTB) was prepared using natural honey as raw material. The as-prepared adsorbent was applied to adsorb Pb2+ from aqueous solution and characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy to investigate the structure and morphology change of the adsorbent before and after Pb2+ adsorption. The influence of the pH, initial Pb2+ concentration, temperature, and contact time on the adsorption of Pb2+ was systematically investigated. The results revealed that the adsorption capacity for Pb2+ is up to 133.2 mg·g−1 at initial pH of 5.0 and adsorption temperature of 298 K. Meanwhile, the adsorption of Pb2+ on HHTB can be well fitted by the pseudo-second-order model and Langmuir isotherm model. The adsorbent had great selectivity for Pb2+ from the aqueous solution containing coexisting ions including Cd2+, Co2+, Cr3+, Cu2+, Ni2+ and Zn2+. Furthermore, the adsorption of Pb2+ on HHTB was attributed to complexation coordination, where it involved hydroxyl and carboxylic groups on HHTB in the process of adsorption of Pb2+.

scholarly journals Application of a Continuous Bipolar Mode Electrocoagulation (CBME) system for polishing distillery wastewater

2019 ◽  
Vol 93 ◽  
pp. 02005 ◽  
Author(s):  
Madhuri Damaraju ◽  
Debraj Bhattacharyya ◽  
Tarun Panda ◽  
Kiran Kumar Kurilla
Keyword(s):  
Reaction Time ◽  
Current Density ◽  
Optimal Point ◽  
Suitable Alternative ◽  
Toc Removal ◽  
Bipolar Mode ◽  
Recalcitrant Carbon ◽  
Initial Ph ◽  
Distillery Wastewater ◽  
Experimental Values

A continuous bipolar mode electrocoagulation (CBME) unit was used in this study for polishing a biologically treated distillery wastewater at laboratory scale. This study focuses on optimizing the process for removal of Total Organic Carbon (TOC) from an anaerobically-treated distillery wastewater. Response surface methodology (RSM) was used for optimizing the process. The study was conducted by varying three operating parameters: Initial pH (2-10), reaction time (0.5-15 min), and current density (13-40 A/sqm). High R-square values, above 0.9, were obtained with ANOVA. Optimal point was observed to be at pH-6.04, Reaction time-11.63 min, current density-39.2 A/sqm. Experimental values of TOC removal at optimal point were found to be 73% against maximum predicted value of 79%. Color removal efficiency was observed to be 85% at the optimal points. It can be concluded that CBME system can be a suitable alternative for removal of recalcitrant carbon and color post-biological treatment in distillery wastewaters.

scholarly journals Synthesis of Nanoscale Zerovalent Iron (nZVI) Supported on Biochar for Chromium Remediation from Aqueous Solution and Soil

2019 ◽  
Vol 16 (22) ◽  
pp. 4430 ◽  
Author(s):  
Haixia Wang ◽  
Mingliang Zhang ◽  
Hongyi Li
Keyword(s):  
Aqueous Solution ◽  
Photoelectron Spectroscopy ◽  
Zero Valent Iron ◽  
Zerovalent Iron ◽  
X Ray ◽  
Nanoscale Zerovalent Iron ◽  
Before And After ◽  
Pseudo Second Order ◽  
Xrd Patterns ◽  
Co Precipitation

Maize straw biochar-supported nanoscale zero-valent iron composite (MSB-nZVI) was prepared for efficient chromium (Cr) removal through alleviating the aggregation of zero-valent iron particles. The removal mechanism of MSB-nZVI was investigated by scanning electron microscopy with energy dispersive X-ray (SEM-EDX), X-ray diffractometry (XRD), and X-ray photoelectron spectroscopy (XPS). Cr(VI) removal from aqueous solution by MSB-nZVI was greatly affected by pH and initial concentration. The removal efficiency of Cr(VI) decreased with increasing pH, and the removal kinetics followed the pseudo-second-order model. XRD patterns of MSB-nZVI before and after reaction showed that reduction and precipitation/co-precipitation (FeCr2O4, Fe3O4, Fe2O3) occurred with the conversion of Cr(VI) to Cr(III) and Fe(0) to Fe(II)/Fe(III). The produced precipitation/co-precipitation could be deposited on the MSB surface rather than being only coated on the surface of nZVI particles, which can alleviate passivation of nZVI. For remediation of Cr(VI)-contaminated saline–alkali soil (pH 8.6–9.0, Cr 341 mg/kg), the released amount of Cr(VI) was 70.7 mg/kg, while it sharply decreased to 0.6–1.7 mg/kg at pH 4.0–8.0, indicating that the saline–alkali environment inhibited the remediation efficiency. These results show that MSB-nZVI can be used as an effective material for Cr(VI) removal from aqueous solution and contaminated soil.

Biosorption of hexavalent chromium from aqueous solution by polyethyleneimine-modified ultrasonic-assisted acid hydrochar from Sargassum horneri

2020 ◽  
Vol 81 (6) ◽  
pp. 1114-1129 ◽  
Author(s):  
Jun Wang ◽  
Qinglong Xie ◽  
Ao Li ◽  
Xuejun Liu ◽  
Fengwen Yu ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Photoelectron Spectroscopy ◽  
Batch Adsorption ◽  
Crosslinking Reaction ◽  
Order Kinetic ◽  
Adsorption Capacities ◽  
Initial Ph ◽  
Ultrasonic Assisted ◽  
Order Kinetic Model ◽  
Pseudo Second Order

Abstract In this study, an efficient route to synthesizing polyethyleneimine-modified ultrasonic-assisted acid hydrochar (PEI-USAH) is developed and reported. Ultrasonic irradiation technique was used as surface modification method to shorten the crosslinking reaction for hydrochar and polyethyleneimine (PEI). The PEI-USAH showed an excellent adsorption capacity for Cr(VI) from aqueous solution. The physicochemical properties of this PEI-modified adsorbent were comparatively characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, Brunauer–Emmett–Teller analysis and CNHS analysis. The effects of contact time, initial pH, and biosorbent dose on adsorption capacities were investigated. The batch adsorption experiments showed that PEI-USAH possessed the maximum adsorption capacities of 94.38 mg/g and 330.84 mg/g for initial Cr(VI) concentration of 100 mg/L and 500 mg/L, respectively. Furthermore, this adsorption process could be fitted to Langmuir adsorption and described by the pseudo second order kinetic model. Based on the above findings, PEI-USAH could be used as a potential adsorbent for removal of Cr(VI) from wastewater.

scholarly journals Current density and residence time in the electrocoagulation process and its influence on Fe2+ reduction [Densidad de corriente y tiempo de residencia en el proceso de electrocoagulación y su influencia en la reducción de Fe+2]

2021 ◽  
Vol 5 (1) ◽  
pp. 29
Author(s):  
Freddy Waldir Gómez Escobedo ◽  
Jorge Edinson Gómez Escobedo ◽  
Erick Alexander Choton Cipriano ◽  
Dagner Marvin Castañeda Hilario ◽  
César Pol Arévalo Aranda ◽  
...  
Keyword(s):  
Acid Mine Drainage ◽  
Current Density ◽  
Mine Drainage ◽  
Research Work ◽  
Residence Times ◽  
Ph Values ◽  
Before And After ◽  
Initial Ph ◽  
Electrocoagulation Process ◽  
Evaluation Parameters

The present research work had as study variables the current density of 20, 40 and 80 mA/cm2 and residence times of 10, 20, 40 and 60 minutes, within these evaluation parameters values were taken of pH, conductivity and Fe2+ removal percentage before and after the electrocoagulation process of artisanal acid mine drainage samples (AMD), the amount of AMD sample per test was 350 mL per test, from the results obtained it could be observed that For the current density of 80 mA/cm2 and a time of 40 minutes, the highest percentage of removal was obtained (76.20%), likewise a minimum percentage of removal of 17.97% was obtained at 20 mA/cm2; The removal percentages are attributed to the effect of the current density of the electrocoagulation process, which allows increasing the initial pH values of the effluent, which in turn allows the formation of precipitates and co-precipitates, in this case of Fe2+.

Electrochemical degradation of safranine T in aqueous solution by Ti/PbO2 electrodes

2020 ◽  
Vol 98 (1) ◽  
pp. 7-14 ◽  
Author(s):  
Baichen Liu ◽  
Bingli Ren ◽  
Yun Xia ◽  
Yang Yang ◽  
Yingwu Yao
Keyword(s):  
Aqueous Solution ◽  
Current Density ◽  
Intermediate Structure ◽  
Electrochemical Degradation ◽  
Reaction Conditions ◽  
First Order Kinetics ◽  
Safranine T ◽  
Initial Ph ◽  
Degradation Reaction ◽  
Optimal Reaction

The electrochemical degradation of safranine T (ST) in aqueous solution was studied. The effects of current density, initial concentration of ST, initial pH values, and Na2SO4 concentration on electrocatalytic degradation of ST in the aqueous solution by Ti/PbO2 electrode were analyzed. The experimental results showed that the electrochemical oxidization reaction of ST fitted a pseudo first order kinetics model. By using the Ti/ PbO2 electrode as the anode, 99.96% of ST can be eliminated at 120 min. It means that the electrochemical degradation of ST in aqueous solution by the Ti/PbO2 electrode was very effective. The optimal reaction conditions were as follows: current density, 40 mA cm−2; initial ST concentration, 100 mg L−1; Na2SO4 concentration, 0.20 mol L−1; initial pH, 6. It can be known from the test of UV–vis and HPLC in the reaction process that the intermediates will be generated, and the possible intermediate structure was studied by HPLC–MS test. However, with the progress of degradation reaction, the intermediates will eventually be oxidized into CO2 and H2O. Cyclic voltammetry and fluorescence experiments proved that ST was indirectly oxidized through the generation of hydroxyl radicals. Under the optimal reaction conditions, the energy required to completely remove ST was 17.92 kWh/m3.

The Study on the Electrocatalytic Treatment of Dye Wastewater by ACF Cathode

2011 ◽  
Vol 356-360 ◽  
pp. 1386-1390
Author(s):  
Jun Sheng Hu ◽  
Yue Li ◽  
Hui Wang
Keyword(s):  
Current Density ◽  
Electrolyte Concentration ◽  
Ph Value ◽  
Strong Adsorption ◽  
Stainless Steel Cathode ◽  
Initial Ph ◽  
Operating Current ◽  
Alkaline Conditions ◽  
Acidic Conditions ◽  
Better Than

By using ACF as the cathode, acid scarlet 3R as simulated wastewater, the experiment researches into the effect of current density, aeration, electrolyte concentration and the initial pH value on the color removal of wastewater. The results showed that: ACF cathode has a strong adsorption capacity. Oxygen is reduced to H2O2 and other oxidizing substances H2O2 on the cathode surface .Therefore, it has a strong degradation capacity to dye, which is far better than that of the stainless steel cathode; Lower operating current density helps reduce processing costs; Higher electrolyte concentration and aeration is not necessarily better, which follows certain rules; The treatment is effected greatly by the initial pH, and the effect of decolonization in the acidic conditions is better than that in alkaline conditions. When the current density is 6Am/cm², electrolyte concentration is 0.04mol•L-1, aeration capacity is 0.2m3/h, initial pH is 3.5 and the time of treatment is 70min, the decolonization rate of wastewater is 95.30 %.

scholarly journals Ni(II) and Cu(II) removal from aqueous solution by a heavy metal-resistance bacterium: kinetic, isotherm and mechanism studies

2017 ◽  
Vol 76 (4) ◽  
pp. 859-868 ◽  
Author(s):  
Haikun Zhang ◽  
Xiaoke Hu ◽  
Hong Lu
Keyword(s):  
Aqueous Solution ◽  
Heavy Metal ◽  
Photoelectron Spectroscopy ◽  
Heavy Metal Resistance ◽  
Metal Resistance ◽  
Dual Model ◽  
X Ray ◽  
Biosorption Process ◽  
Before And After ◽  
Acinetobacter Sp

The potentiality of a heavy metal-resistance bacterium Acinetobacter sp. HK-1 for removing Ni(II) and Cu(II) ions from aqueous solution and the biosorption mechanism were investigated in this study. The effects of pH, contact time and Ni(II)/Cu(II) concentration on the adsorption process were evaluated and the maximum biosorption capacity of strain HK-1 was found to be 56.65 mg/g for Ni(II) and 157.2 mg/g for Cu(II), respectively. The experimental kinetic data fit well with the pseudo-second-order model (R2 > 0.98) and the biosorption process was best explained by the Langmuir-Freundlich dual model (R2 > 0.97). The morphologies of HK-1 before and after adsorption in a Ni(II)/Cu(II) supplemented system were compared using a scanning electron microscope. After adsorption, the valence state of Ni(II)/Cu(II) was not changed and the formation of nickel/copper phosphate was observed using X-ray photoelectron spectroscopy (XPS) and X-ray diffraction. The results of Fourier transform infrared spectroscopy and XPS further indicated that amine, phosphate and carboxyl groups were involved in the biosorption process. Cu(II) biosorption by Acinetobacter sp. was firstly reported. Based on the above results, it can be concluded that Acinetobacter sp. HK-1 has a promising application in Ni(II) and Cu(II) ion removal from industrial wastewater.

scholarly journals Adsorptive Removal of Malachite Green Dye from Aqueous Solution Using Chemically Modified Charred and Xanthated Wheat Bran

2020 ◽  
Vol 41 (1) ◽  
pp. 103-109
Author(s):  
Dilli Dhami ◽  
Puspa Lal Homagai
Keyword(s):  
Aqueous Solution ◽  
Malachite Green ◽  
Wheat Bran ◽  
Ph Effect ◽  
Attractive Alternative ◽  
Adsorptive Removal ◽  
Chemically Modified ◽  
Malachite Green Dye ◽  
Before And After ◽  
Initial Ph

Adsorptive removal of Malachite Green (MB) dye from aqueous solution using chemically modified Wheat Bran has been investigated. Wheat bran was chemically modified to charred through charring process and it was further modified to xanthated through xanthation process. Batch experiments were carried out to study the experimental parameters such as effect of pH, effect of concentration and effect of contact time for both Charred Wheat Bran (CWB) and Xanthated Wheat Bran (XWB) simultaneously. The concentrations of dye ions before and after the adsorption were determined by using UV-Visible Spectrophotometer. The dye uptake was maximum for the initial pH of 4 for both CWB and XWB but the percentage removal for XWB was found to be effective in comparison with CWB i.e., 98.45% and 93.45% respectively with adsorbent dose of 0.025g and agitation speed of 190 rpm. The applicability of Langmuir isotherm was tested. The adsorption capacity of MG dye into CWB and XWB was found to be 69 mg/g and 112.9 mg/g, respectively. Similarly, the kinetic data best fitted for pseudo-second order. Hence, the result showed that XWB may be an attractive alternative for the removal of MG dye from aqueous solution in comparison to CWB as bio-adsorbent.

scholarly journals Biosorption of methylene blue by nonliving biomass of the brown macroalga Sargassum hemiphyllum

2017 ◽  
Vol 76 (6) ◽  
pp. 1574-1583 ◽  
Author(s):  
Jianfeng Liang ◽  
Jianrong Xia ◽  
Jianyou Long
Keyword(s):  
Methylene Blue ◽  
Functional Groups ◽  
Photoelectron Spectroscopy ◽  
Algal Biomass ◽  
Order Kinetic ◽  
Before And After ◽  
Initial Ph ◽  
Order Kinetic Model ◽  
Ft Ir ◽  
Sargassum Hemiphyllum

The ability of Sargassum hemiphyllum to remove methylene blue (MB) from aqueous solution was evaluated. Batch experiments were conducted to examine the effects of parameters such as initial pH, contact time, biomass dose and initial dye concentration on adsorption capacity. S. hemiphyllum before and after MB adsorption was characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The Langmuir isotherm model provided the best correlation with experimental data, and the monolayer biosorption capacity was 729.93 mg·g−1 within 120 min using 0.5 g·L−1 algal biomass and pH of 5. The pseudo-second-order kinetic model accurately described the adsorption kinetics data. Thermodynamic parameters (ΔG0, ΔH0 and ΔS0) at temperature ranges of 293–313 K demonstrated that biosorption is an endothermic and spontaneous reaction. FT-IR analysis showed that the hydroxyl, amine and carboxyl functional groups on the surface of the algae were the most important functional groups for biosorption of MB. XPS analysis indicated that the algal biomass combined with MB molecules through –NH2 groups. These results suggest that S. hemiphyllum is a favorable biosorbent for removing MB dye from wastewater.

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