Influence of Operational Parameters on Photocatalytic Degradation of Linuron in Aqueous TiO2 Pillared Montmorillonite Suspension

TiO2 pillared clay was prepared by intercalation of titan polyoxocation into interlamelar space of an Algerian montmorillonite and used for the photocatalytic degradation of the linuron herbicide as a target pollutant in aqueous solution. The TiO2 pillared montmorillonite (Mont-TiO2) was characterized by X-ray photoelectron spectroscopy (XPS), X-Ray diffraction (XRD), X-Ray fluorescence (XRF), scanning electronic microscopy (SEM), thermogravimetry and differential thermal analysis (TG-DTA), Fourier transformed infra-red (FT-IR), specific area and porosity determinations. This physicochemical characterization pointed to successful TiO2 pillaring of the clay. The prepared material has porous structure and exhibit a good thermal stability as indicated by its surface area after calcination by microwave. The effects of operating parameters such as catalyst loading, initial pH of the solution and the pollutant concentration on the photocatalytic efficiency and COD removal were evaluated. Under initial pH of the solution around seven, pollutant concentration of 10 mg/L and 2.5 g/L of catalyst at room temperature, the degradation efficiency and COD removal of linuron was best then the other operating conditions. It was observed that operational parameters play a major role in the photocatalytic degradation process. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

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Catalytic Ozonation for Effective Degradation of Coal Chemical Biochemical Tail Water by Mn/Ce@RM Catalyst

Water ◽

10.3390/w14020206 ◽

2022 ◽

Vol 14 (2) ◽

pp. 206

Author(s):

Yicheng Wang ◽

Yingkun Wang ◽

Xi Lu ◽

Wenquan Sun ◽

Yanhua Xu ◽

...

Keyword(s):

Reaction Time ◽

Removal Rate ◽

Catalytic Ozonation ◽

Operating Conditions ◽

Cod Removal ◽

X Ray ◽

Initial Ph ◽

Catalyst Dosage ◽

Cod Removal Rate ◽

Tail Water

An Mn/Ce@red mud (RM) catalyst was prepared from RM via a doping–calcination method. Scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy were used to characterize the surface morphology, crystal morphology, and elemental composition of the Mn/Ce@RM catalyst, respectively. In addition, preparation and catalytic ozonation conditions were optimized, and the mechanism of catalytic ozonation was discussed. Lastly, a fuzzy analytic hierarchy process (FAHP) was adopted to evaluate the degradation of coal chemical biochemical tail water. The best preparation conditions for the Mn/Ce@RM catalyst were found to be as follows: (1) active component loading of 3%, (2) Mn/Ce doping ratio of 2:1, (3) calcination temperature of 550 °C, (4) calcination time of 240 min, and (5) fly ash floating bead doping of 10%. The chemical oxygen demand (COD) removal rate was 76.58% under this preparation condition. The characterization results suggested that the pore structure of the optimized Mn/Ce@RM catalyst was significantly improved. Mn and Ce were successfully loaded on the catalyst in the form of MnO2 and CeO2. The best operating conditions in the study were as follows: (1) reaction time of 80 min, (2) initial pH of 9, (3) ozone dosage of 2.0 g/h, (4) catalyst dosage of 62.5 g/L, and (5) COD removal rate of 84.96%. Mechanism analysis results showed that hydroxyl radicals (•OH) played a leading role in degrading organics in the biochemical tail water, and adsorption of RM and direct oxidation of ozone played a secondary role. FAHP was established on the basis of environmental impact, economic benefit, and energy consumption. Comprehensive evaluation by FAHP demonstrated that D3 (with an ozone dosage of 2.0 g/H, a catalyst dosage of 62.5 g/L, initial pH of 9, reaction time of 80 min, and a COD removal rate of 84.96%) was the best operating condition.

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Property of Cu2O-CuO/ZSM-5 nanocomposite and degradation process of azo dye AO7 without sacrificial agent (H2O2)

Water Science & Technology ◽

10.2166/wst.2016.138 ◽

2016 ◽

Vol 73 (11) ◽

pp. 2747-2753 ◽

Cited By ~ 2

Author(s):

Wusong Kong ◽

Hongxia Qu ◽

Peng Chen ◽

Weihua Ma ◽

Huifang Xie

Keyword(s):

Catalytic Activity ◽

Aqueous Solutions ◽

Photoelectron Spectroscopy ◽

Oxygen Demand ◽

Operating Conditions ◽

Surface Element ◽

Impregnation Method ◽

X Ray ◽

Initial Ph ◽

Sacrificial Agent

In this study, Cu2O-CuO/ZSM-5 nanocomposite was synthesized by the impregnation method, and its catalytic performance for the destruction of AO7 in aqueous solutions was investigated. The morphology, structure and surface element valence state of Cu2O-CuO/ZSM-5 were characterized by transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The operating conditions on the degradation of AO7 by Cu2O-CuO/ZSM-5, such as initial pH values, concentration of AO7 and catalyst dosage were investigated and optimized. The results showed that the sample had good catalytic activity for destruction of AO7 in the absence of a sacrificial agent (e.g. H2O2): it could degrade 91% AO7 in 140 min at 25 °C and was not restricted by the initial pH of the AO7 aqueous solutions. Cu2O-CuO/ZSM-5 exhibited stable catalytic activity with little loss after three successive runs. The total organic carbon and chemical oxygen demand removal efficiencies increased rapidly to 69.36% and 67.3% after 120 min of treatment by Cu2O-CuO/ZSM-5, respectively.

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Surfactant-Free Microwave-Assisted Synthesis of Fe-Doped ZnO Nanostars as Photocatalyst for Degradation of Tropaeolin O in Water under Visible Light

Journal of Nanomaterials ◽

10.1155/2015/190747 ◽

2015 ◽

Vol 2015 ◽

pp. 1-9 ◽

Cited By ~ 7

Author(s):

Tsz-Lung Kwong ◽

Ka-Fu Yung

Keyword(s):

Visible Light ◽

Photocatalytic Degradation ◽

Irradiation Time ◽

Catalyst Loading ◽

Orthogonal Experimental Design ◽

Microwave Assisted Synthesis ◽

X Ray ◽

Microwave Assisted ◽

Vis Spectroscopy ◽

Doped Zno

Iron-doped zinc oxide nanostar was synthesized by the microwave-assisted surfactant-free hydrolysis method. The as-synthesized Fe-doped ZnO nanostars catalyst was fully characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), powder X-ray diffraction (XRD), and diffuse reflectance UV-vis spectroscopy (UV-DRA). The photocatalytic activity of the photocatalyst was investigated for the photocatalytic degradation of Tropaeolin O under visible light irradiation. It is observed that the doping of Fe ions enhances the absorption of the visible light and thus the photocatalytic degradation rate of Tropaeolin O would increase. Despite the Taguchi orthogonal experimental design method, the photocatalytic conversion could be achieved at 99.8% in the Fe-doped ZnO catalyzed photodegradation reaction under the optimal reaction conditions of catalyst loading (30 mg), temperature (60°C), light distance (0 cm), initial pH (pH = 9), and irradiation time (3 h). The Fe-doped ZnO photocatalyst can also be easily recovered and directly reused for eight cycles with over 70% conversion.

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Photocatalytic Activity of Ag-TiO2 Composites Deposited by Photoreduction under UV Irradiation

International Journal of Photoenergy ◽

10.1155/2018/6080432 ◽

2018 ◽

Vol 2018 ◽

pp. 1-8 ◽

Cited By ~ 9

Author(s):

Carlos Díaz-Uribe ◽

Jose Viloria ◽

Lorraine Cervantes ◽

William Vallejo ◽

Karen Navarro ◽

...

Keyword(s):

Thin Films ◽

Raman Spectroscopy ◽

Photocatalytic Activity ◽

Photocatalytic Degradation ◽

Uv Irradiation ◽

Ag Nanoparticles ◽

Nitrate Solution ◽

Physicochemical Characterization ◽

Soda Lime Glass ◽

X Ray

In this work, we synthesized Ag nanoparticles on TiO2 thin films deposited on soda lime glass substrates. Ag nanoparticles were synthesized by photoreduction under UV irradiation silver nitrate solution. X-ray diffraction, Raman spectroscopy, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) measurements were used for physicochemical characterization. The structural study showed that all samples were polycrystalline, main phases were anatase and rutile, and no additional signals were detected after surface modification. Raman spectroscopy suggested that silver aggregates deposited on the TiO2 films could exhibit the surface plasmon resonance (SPR) phenomenon; XPS and SEM analysis confirmed TiO2 film morphological modification after photoreduction process. Photocatalytic degradation of methylene blue (MB) was studied under UV irradiation in aqueous solution, and, besides, pseudo-first-order model was used to obtain kinetic information about photocatalytic degradation. Results indicated that Ag-TiO2 showed an important increase in photocatalytic activity under UV (from 20% to 35%); finally, Ag-TiO2 thin films had kapp value 2.4 × 10−3 ± 0.003 min−1 of 1.8 times greater than the kapp value 1.3 × 10−4 ± 0.0004 min−1 of TiO2 thin films.

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Methylene Blue Photodegradation under Visible Irradiation on Ag-Doped ZnO Thin Films

International Journal of Photoenergy ◽

10.1155/2020/1627498 ◽

2020 ◽

Vol 2020 ◽

pp. 1-11 ◽

Cited By ~ 8

Author(s):

William Vallejo ◽

Alvaro Cantillo ◽

Carlos Díaz-Uribe

Keyword(s):

Thin Films ◽

Methylene Blue ◽

Raman Spectroscopy ◽

Photocatalytic Degradation ◽

Physicochemical Characterization ◽

Zno Thin Films ◽

Visible Range ◽

X Ray ◽

Visible Irradiation ◽

Doped Zno

This study synthesized and characterized Ag-doped ZnO thin films. Doped ZnO powders were synthesized using the sol-gel method, and thin films were fabricated using the doctor blade technique. The Ag content was determined by optical emission spectrometers with inductively coupled plasma (ICP plasma). Additionally, X-ray diffraction, Raman spectroscopy, Atomic Force Microscopy (AFM), diffuse reflectance, and X-ray photoelectron spectroscopy (XPS) measurements were used for physicochemical characterization. Finally, the photocatalytic degradation of methylene blue (MB) was studied under visible irradiation in aqueous solution. The Langmuir-Hinshelwood model was used to determine the reaction rate constant of the photocatalytic degradation. The physicochemical characterization showed that the samples were polycrystalline, and the diffraction signals corresponded to the ZnO wurtzite crystalline phase. Raman spectroscopy verified the ZnO doping process. The AFM analysis showed that roughness and grain size were reduced after the doping process. Furthermore, the optical results indicated that the presence of Ag improved the ZnO optical properties in the visible range, and the Ag-doped ZnO thin films had the lowest band gap value (2.95 eV). Finally, the photocatalytic degradation results indicated that the doping process enhanced the photocatalytic activity under visible irradiation, and the Ag-doped ZnO thin films had the highest MB photodegradation value (45.1%), as compared to that of the ZnO thin films (2.7%).

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Optimization of electrocoagulation operating parameters for COD removal from olive mill wastewater: application of Box-Behnken design

Mediterranean Journal of Chemistry ◽

10.13171/mjc93191011240kea ◽

2019 ◽

Vol 9 (3) ◽

pp. 212-221

Author(s):

Fatima Erraib ◽

Khalid El Ass

Keyword(s):

Response Surface ◽

Chloride Concentration ◽

Oxygen Demand ◽

Olive Mill Wastewater ◽

Operating Conditions ◽

Cod Removal ◽

Coefficient Of Determination ◽

Box Behnken Design ◽

Initial Ph ◽

Olive Mill

Box–Behnken response surface design was successfully employed to optimize and study the olive mill wastewater (OMW) treatment by electrocoagulation (EC) process. The influence of four decisive factors were modelled and optimized to increase the removal of chemical oxygen demand (COD). The Box–Behnken design (BBD) results were analyzed and the second-order polynomial model was developed using multiple regression analysis. The model developed from the experimental design was predictive and a good fit with the experimental data with a high coefficient of determination (R2 ) value (more than 0.98). The optimal operating conditions based on Derringer’s desired function methodology are found to be; initial pH of 4.4, a current density of 27.6 mA/cm2 , electrolysis time of 14.1 min, and chloride concentration of 3.2 g/L. Under these conditions, the predicted COD removal efficiency was found to be 67.14% with a desirability value of 0.94. These experimental results were confirmed by validation experiments and proved that Box–Behnken design and response surface methodology could efficiently be applied for modelling of COD removal from OMW.

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Ag–TiO2 Nanofiber Membranes for Photocatalytic Degradation of Dyes

Advanced Science Letters ◽

10.1166/asl.2018.12193 ◽

2018 ◽

Vol 24 (8) ◽

pp. 5764-5767

Author(s):

Abhinav K Nair ◽

P. E JagadeeshBabu

Keyword(s):

Photocatalytic Degradation ◽

Dye Removal ◽

Ultra Violet ◽

Catalyst Loading ◽

X Ray Diffraction ◽

X Ray ◽

Violet Light ◽

Tio2 Nanofiber ◽

Degradation Of Dyes ◽

Nanofiber Membranes

TiO2 nanoparticles have been widely studied for photocatalytic degradation of dyes, but their small size makes catalyst recovery difficult. When compared to TiO2 nanoparticles, nanofibers are larger in size and exhibit good photocatalytic activity. Doping TiO2 with suitable modifiers like silver can further boost their performance. In the present work, TiO2 nanofibers were synthesized using hydrothermal method. The obtained TiO2 fibers were then doped with silver via photo-deposition method under ultra-violet light irradiation. Scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy and X-ray diffraction were used to characterize the nanofibers. Future, these nanofibers were used to synthesize a hierarchical photocatalytic membrane to enable continuous degradation and filtration. The effects of catalyst loading on permeation and dye removal were studied using rhodamine B. The silver doped TiO2 nanofiber membranes exhibited good dye removal capabilities.

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Cost-effective removal of COD in the pre-treatment of wastewater from the paper industry

Water Science & Technology ◽

10.2166/wst.2019.328 ◽

2019 ◽

Vol 81 (7) ◽

pp. 1345-1353 ◽

Cited By ~ 2

Author(s):

Joanna Boguniewicz-Zablocka ◽

Iwona Klosok-Bazan ◽

Vincenzo Naddeo ◽

Clara A. Mozejko

Keyword(s):

Wastewater Treatment ◽

High Efficiency ◽

Paper Industry ◽

Cost Effective ◽

Operating Conditions ◽

Cod Removal ◽

Process Efficiency ◽

Effective Removal ◽

Initial Ph ◽

Pre Treatment

Abstract The present paper reveals results of research for cost-effective removal of chemical oxygen demand (COD) contained in industrial paper mill effluent. Not only process efficiency but also wastewater treatment costs are discussed. Different pre-treatment processes are applied aiming to investigate the COD removal before discharge to the municipal sewage network. The objective of this paper is to find the optimal operating conditions for the coagulation process. The effects of key operational parameters, including the type of coagulant, initial pH, temperature and coagulant dose, on COD percentage removal were investigated. The laboratory experiments confirmed the high efficiency of chemically enhanced mechanical treatment towards COD. The data obtained show that even low dose of chemicals provides sufficient COD reduction. The initial pH of the wastewater had a significant impact on the COD removal. Under the optimal operational conditions (pH = 7.5, T = 18 °C) the treatment of wastewater from paper industries by coagulation has led to a reduction of 70% COD for wastewater discharged. In terms of the investigated paper industry wastewater, polyaluminium chloride appears to be most suitable for treatment of high COD concentration. However, in an economic evaluation of requirements for wastewater treatment, operating costs and associated saving were such that PAX was more favourable.

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Arsenic removal efficiency and mechanisms by electro-chemical precipitation process

Water Science & Technology ◽

10.2166/wst.2002.0250 ◽

2002 ◽

Vol 46 (9) ◽

pp. 247-254 ◽

Cited By ~ 13

Author(s):

A. Pinisakul ◽

C. Polprasert ◽

P. Parkpian ◽

J. Satayavivad

Keyword(s):

Arsenic Removal ◽

Chemical Precipitation ◽

Operating Conditions ◽

Precipitation Process ◽

Contaminated Water ◽

X Ray ◽

Drinking Water Standard ◽

Initial Ph ◽

Electrical Gradient ◽

Balance Analysis

This research was conducted to investigate the efficiency and mechanisms of arsenic (As) removal from a contaminated water by using the electro-chemical precipitation (ECP) process, with the operating conditions as follows: initial As concentration of 0.5-5 mg/L, 0.1 M KCl, electrical gradient of 200 V/m and initial pH higher than 3. The laboratory-scale ECP unit was able to reduce As to within the WHO drinking water standard of 0.01 mg/L in 20 min. The ClÐ salt was found to yield better As removal efficiencies than the NO3− salt probably because NO3− ions interfered with the production of OH− and Fe(OH)3, important for As removal. X-ray fluorescence and X-ray diffractometric analysis revealed maghemite (Fe2O3) and angelellite (Fe4As2O11) to be the major compounds present in the precipitated sludge. The percent Fe2O3 and Fe4As2O11 contents of the dried ECP sludge were 98.29% and 0.26%, respectively. From a mass balance analysis, As removal in the ECP process was due to: incorporation in and adsorption on the ECP sludge - 64.9-94.9%, conversion to arsine (AsH3) gas - 10.5-15.6%, adsorption on the electrode plates and reactor walls - 0.03-1.1%, residual in the supernatant - 0.2-0.4%, and unaccounted for - 1.2-19.8%.

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Submerged Membrane Photo Reactor (SMPR) with Simultaneous Photo Degradation and TiO2 Catalyst Recovery for Efficient Dyes Removal

ASEAN Journal of Chemical Engineering ◽

10.22146/ajche.65952 ◽

2021 ◽

Vol 21 (2) ◽

pp. 225

Author(s):

Dessy Ariyanti ◽

Filicia Wicaksana ◽

Wei Gao

Keyword(s):

Hollow Fiber Membrane ◽

Binary Solution ◽

Synergetic Effect ◽

Operating Conditions ◽

Optimum Operating ◽

Catalyst Loading ◽

Permeate Flux ◽

Operational Parameters ◽

Catalyst Recovery ◽

Low Catalyst Loading

In this study, a polyvinylidene difluoride (PVDF) hollow fiber membrane module incorporated with TiO2 was submerged into a photocatalytic reactor to create a hybrid photocatalysis with membrane separation process (a submerged membrane photoreactor, SMPR), for advanced dyes wastewater treatment. The SMPR performance was assessed by the degradation of single component Rhodamine B (RhB) and degradation of mixed dyes (RhB and Methyl orange (MO)) in a binary solution. Several operational parameters such as the amount of catalyst loading, permeate flux, and the effect of aeration were studied. Fouling tendency on the membrane was also investigated to determine the optimum operating conditions. The results show that the synergetic effect of the low catalyst loading and permeate flux creates the environment for optimum light penetration for high photocatalytic activity as the hybrid system with low catalyst loading (0.5 g/L) and 66 L/m2h of flux with aeration at 1.3 L/min has proven to increase the photocatalysis performance by 20% with additional catalyst recovery. In addition, applying the low catalyst loading and flux permeate with aeration brings minimal fouling problems.

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