Peroxide Process Research Articles

Revisiting the Role of Dissolved Silicate in Catalyzing the Hydrogen Peroxide Process with Iron-Bearing Minerals.

Injecting H2O2 into aquifers is a widely used in-situ chemical oxidation (ISCO) technology for groundwater remediation. Dissolved silicate was reported to decrease the reactivity of iron (Ⅲ)-bearing minerals toward H2O2. In this study, the effect of naturally occurring levels of dissolved silicate (≤1 mM) on the catalyzing hydrogen peroxide (CHP) with Fe(II) minerals is revaluated, and new observations that contradict with previous studies are reported. Specifically, dissolved silicate enhanced the CHP process by Fe(II) minerals. In the presence of Fe(II) minerals, siderite and ferrous oxide (FeO), which had a stronger dissolution tendency than Fe(III) minerals, dissolved silicate could prevent the dissolved iron species from precipitation through a coordinating effect, therefore reinforcing the homogeneous CHP process and the degradation of 2,4-dichlorophenol. The solution pH decreased due to the generation of degradation intermediates, and the solution acidification in turn promoted further dissolution of Fe(II) minerals. FeO particles exhibited the strongest silicate adsorption among the minerals, therefore a higher initial silicate concentration of 1 mM was needed to observe the enhancing effect. This study redefines the role of dissolved silicate on CHP process and provides clues to the design of efficient H2O2-based ISCO system for the remediation of groundwater.

Rapid oxidation of acetaminophen with zero-valent copper induced hydrogen peroxide process in presence of ferric ion and chloride ion

Zero-valent copper-triggered hydrogen peroxide (Cu0/H2O2) process was widely used for the degradation of pollutants, while its oxidation efficacy was restrained by the interaction of Cu+ with O2 as well as the dismutation of Cu+. In this study, both ferric ion (Fe3+) and chloride ion (Cl−) were introduced into the Cu0/H2O2 (Fe3+/Cl−/Cu0/H2O2) system, and the removal of acetaminophen was immensely enhanced. In the Fe3+/Cl−/Cu0/H2O2, Fe3+ was converted to Fe2+ via the reaction of Fe3+ with Cu0 and Cu+, and the reaction between Cu+ and Fe3+ receded the reaction of Cu+ with O2, promoting the formation of reactive oxygen species; Cl− integrated with Cu+ to form the Cu-Cl chelate, and Cl− helped the comproportionation of Cu0 and Cu2+ to form CuCl, which decreased the reaction of Cu+ with O2 and promoted the generation of reactive oxygen species. Both the addition of Fe3+ and Cl− in the Cu0/H2O2 process greatly improved the utilization of Cu0. •OH, Various reactive oxygen species such as •OH, FeIVO2+ and reactive chlorine species were identified in the Fe3+/Cl−/Cu0/H2O2 process. There into, Fe2+ stimulated H2O2 to form •OH and FeIVO2+, and Cu+ triggered H2O2 to form •OH rather than Cu3+, and partial •OH was transferred to reactive chlorine species via the interaction of •OH with Cl−. After increasing the solution pH to > 7.0 and leaching solution, the total copper of reaction solution was below 0.455 mg/L. These results suggested that the Fe3+/Cl−/Cu0/H2O2 process was feasible, effective and environmentally safe, and the research offered a theory instruction for the application of Fe3+ and Cl−-enhanced Cu0/H2O2 process in pollutants decomposition.

Eco‐efficiency improvements in the propylene‐to‐epichlorohydrin process

AbstractBACKGROUNDEpichlorohydrin (ECH) production is an important industrial process, owing to its importance in windmill blade manufacture, but it suffers from several drawbacks such as high energy use, large wastewater production and low atom efficiency. This original study investigates a novel chlorohydrin‐free technology with an enhanced separation system for ECH production. Rigorous process simulations were performed in Aspen Plus for the classic and novel processes, and a fair techno‐economic and sustainability comparison was made between the new catalytic oxidation route and the classic chlorohydrin process.RESULTSFor the hydrogen peroxide (HP) process route, a novel separation system was developed using methanol as solvent, which enables high purity of ECH. Moreover, allyl chloride (ACH) purification was optimized using thermally coupled distillation to improve the energy efficiency of ACH production. The novel HP process provides 88% higher atom efficiency, about 10% higher yield and a smaller amount of by‐products, as well as a 13% increase in production capacity and major savings of 98% in wastewater production, while also achieving lower energy use (<40 MJ kg−1 ECH) and reduced carbon dioxide emission (1.13 kg kg−1 ECH).CONCLUSIONThe developed HP process route is feasible and economically viable. Also, it can be partly retrofitted to existing ECH plants based on the chlorohydrin route. As both processes use the same intermediate product, only the ECH part of a classic process would be replaced by the novel route, while keeping the common ACH part. This approach is the most profitable, as only 55% of capital expenditure is required for this modification, while the plant would benefit from all the improvements provided by the novel process. © 2023 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).

Investigation of degradation and transformation product formation during the UV/H2O2-based oxidation process for chemicals of emerging concern

This study aimed to optimize the ultraviolet (UV)/hydrogen peroxide (H2O2) process for degrading chemicals of emerging concern (CECs), such as caffeine (CAF), atenolol (ATL), acetaminophen (ACT), and chlortetracycline (CTC). The CECs used in this study were chosen because they are used in various industries, affect water bodies, and are difficult to degrade using conventional oxidation and biological processes. The individual degradation results revealed that the CAF degradation rate increased from 23 ± 2%–80 ± 4% as the UV/H2O2 dose increased from 1 to 10 mg·L−1. Similarly, the ATL, ACT, and CTC degradation rates increased from 59.23 ± 2%, 34.21 ± 1.9%, and, 41.36 ± 2.3%–91.24 ± 3%, 68.12 ± 3%, and 91.93 ± 3.1%, respectively. The complex feed water analysis results revealed that CTC had a higher degradation rate than the other targeted contaminants owing to its higher degradation potential. The rate of reaction results revealed that the degradation of these CECs followed the pseudo-first-order reaction, with R2 > 0.95 in all cases. liquid chromatography with tandem mass spectrometry (LC–MS/MS) was used to identify the degradation products, and the results revealed the presence of low-molecular-weight organic products due to oxidation. The organic products were formed because of the hydroxylation and demethylation of intermediates and photoproducts, which caused a ring opening and generated several low-molecular-weight carboxylic acids before complete mineralization. These results illustrate that the UV/H2O2 process had some significant effects on the complex mixture. However, CTC exhibited a relatively high degradation rate, which is believed to have inhibited the degradation of other chemicals.

Ridding the World of 'Rogues': Improving Vapor Phase H2O2 Sterilization and Decontamination Processes.

This publication reviews the reported 'rogue' behavior of biological indicators used for vapor phase hydrogen peroxide processes with attention to the aspects of BI design / configuration to identify factors which may contribute to the reported greater variance in resistance. The contributing factors are reviewed with respect to the unique circumstances of a vapor phase process that adds challenges to H2O2 delivery to the spore challenge. The numerous complexities of H2O2 vapor phase processes are described as these contribute to the difficulties encountered. The paper includes specific recommendations for changes to the biological indicator configurations in use and the vapor process to reduce the incidence of rogues.

Comparing Hydrogen Peroxide and Sodium Perborate Ultraviolet Advanced Oxidation Processes for 1,4-Dioxane Removal from Tertiary Wastewater Effluent

Ultraviolet advanced oxidation processes (UV-AOPs) were compared using sodium perborate (UV/NaBO3 AOP) or hydrogen peroxide (UV/H2O2 AOP) for 1,4-dioxane removal from tertiary wastewater effluent. Both UV-AOPs were also tested with the addition of acetic acid. Results revealed that sodium perborate performed similarly to hydrogen peroxide. The UV/NaBO3 AOP with 6 milligrams per liter (mg/L) as H2O2 resulted in 43.9 percent 1,4-dioxane removal, while an equivalent UV/H2O2 AOP showed 42.8 percent removal. Despite their similar performance, NaBO3 is approximately 3.3 times more expensive than H2O2. However, the solid form of NaBO3 can provide a major benefit to remote and mobile operations. Unlike H2O2 solution, which degrades over time and requires repeated costly shipments, NaBO3 is a convenient source of H2O2, and a long-term supply can be shipped at once and mixed into solution as needed. The addition of acetic acid to a UV/H2O2 AOP was found to enhance 1,4-dioxane removal, increasing treatment effectiveness by 5.7%.

A versatile Fe2+/urea hydrogen peroxide advanced oxidation process for not only organoarsenic remediation but also nitrogen supplement in soil

Organoarsenics in soil urgently desired careful remediation. Unfortunately, it did not receive enough attention. Herein, we report a versatile Fe2+/Urea Hydrogen Peroxide (UHP) process for not only organoarsenic remediation but also nitrogen supplement in soil. Insight mechanism was firstly studied in water. Roxarsone (ROX) was efficiently degraded by 99.6% following a kinetics of v= 33.91 × [ROX]× [UHP]1.2175 × [Fe2+]1.8990. Aromatic ring cleavage of ROX was realized, resulting in a satisfying mineralization performance. After degradation processes, 88.5% of total arsenic was removed from the solution at pH 5.0 via adsorption processes by generated Fe(OH)3 particles. The particles showed much higher adsorption capacity to inorganic arsenic species than that to organoarsenic. The degradation of ROX facilitated the immobilization of total arsenic. The remediation was further carried out in soil. Satisfying removal of ROX (95.5%) and immobilization of total arsenic (89.3%) was achieved. More importantly, 94.2%− 94.6% less arsenic was transferred into the lettuce. By the injection of Fe2+/UHP, a sixteen times higher concentration of total nitrogen was achieved. The growth of lettuce was significantly promoted due to the multi-functions including arsenic immobilization and nitrogen supplement. The achievements suggested Fe2+/UHP system potentials in applications for organoarsenic remediation in soil and also soil amelioration.

Effect of the Concentration of Cations (Ca2+, Mg2+, Na+, and K+) in Water on the Level of Oxidative Processes in the Tissues of Bivalves of the Family Dreissenidae

The results of studying the influence of the content of Ca2+, Mg2+, Na+, and K+ cations in water on the level of lipid peroxidation products and antioxidants in the tissues of bivalve mollusks, D. bugensis and D. polymorpha, are presented. Mollusks were caught in four water areas of the Gorky Reservoir, which differ in the concentrations of Ca2+, Mg2+, Na+, and K+ cations. A correlation relationship has been established between the quantitative parameters of cations in water and the intensity of peroxide processes, on the one hand, and the level of general antioxidant activity in mollusk tissues, on the other. Statistically significant interspecific differences in the studied parameters have been recorded in mollusks from areas with an increased concentration of cations.

A mini-review on MOFs activated peroxide processes and the enhancement with the external energy

Over the past decade, metal–organic frameworks (MOFs) have received tremendous interest in a wide variety of fields, particularly in water purification, thanks to their large surface area, adjustable topologies and high physicochemical tunability. Herein, we present an in-depth overview of MOFs materials currently available in the heterogeneous advanced oxidation processes (AOPs) for water treatment, via radical (including •OH, SO4•−, O2•−, etc.) and/or nonradical (1O2, for example) mediated oxidation. The emphasis is made on the recent advance of diverse MOFs, as effective peroxide activators to generate reactive oxygen species (ROS) for organic contaminant removal in water. The further enhancements in MOFs activated peroxide processes with the photo-, electro-, and ultrasonic-assisted strategies are summarized based on the state-of-the-art development in this field. The detailed discussions have also focused on the specific behaviors, modulation strategies, role of reactive sites and mechanism of ROS formation in these MOFs activated peroxide systems. In the end, the challenge of large-scale synthesis and industrial application of MOFs towards peroxide activation is proposed, which implies great application potential of MOFs-based materials for environmental remediation.

Degradation of refractory organic matter in MBR effluent from treating landfill leachate by UV/PMS and UV/H2O2: a comparative study

ABSTRACT This study applied ultraviolet/peroxymonosulfate (UV/PMS) and UV/hydrogen peroxide (UV/H2O2) processes to the advanced treatment of membrane bioreactor (MBR) effluent. The degradation efficiency of refractory organic matter and the reaction mechanisms of the two processes were systematically investigated. The results showed that the degradation efficiency of the UV/PMS processes was significantly lower than that of the UV/H2O2 process when the PMS concentration was significantly lower than the H2O2 concentration, e.g. the UV254 removals under optimal conditions were 72.92% and 82.21%, respectively. Additionally, the UV/PMS process could operate over a broader pH range. The degradation efficiency of the UV/PMS process was slightly increased by HCO3 – and Cl- due to the activation of PMS, while in the UV/H2O2 process, HCO3 - and Cl- depressed the degradation efficiency by competing with organic matter to react with reactive oxygen species (ROS). After the two processes, the aromaticity, humification, condensation degree, and molecular weight of refractory organic matter in the MBR effluent were considerably decreased. Fulvic- (HA) and humic-like substances (FA) were greatly degraded by the two processes. The UV/PMS had a superior degradation efficiency for macromolecular HA in the early stage of the reaction, and the UV/H2O2 could degrade HA to protein-like substances in the latter stage of the reaction. These differences between the two processes could be attributed to the dominance of different ROS, with SO4 •- and HO• dominating in the UV/PMS, and HO• dominating in the UV/H2O2. The results of this study provide theoretical support for the application of MBR effluent treatment.

Extraction and Characterization of Fiber and Cellulose from Ethiopian Linseed Straw: Determination of Retting Period and Optimization of Multi-Step Alkaline Peroxide Process

Flax is a commercial crop grown in many parts of the world both for its seeds and for its fibers. The seed-based flax variety (linseed) is considered less for its fiber after the seed is extracted. In this study, linseed straw was utilized and processed to extract fiber and cellulose through optimization of retting time and a multi-step alkaline peroxide extraction process using the Taguchi design of experiment (DOE). Effects of retting duration on fiber properties as well as effects of solvent concentration, reaction temperature, and time on removal of non-cellulosic fiber components were studied using the gravimetric technique, Fourier transform infrared (FTIR) spectroscopy and thermal studies. Based on these findings, retting for 216 h at room temperature should offer adequate retting efficiency and fiber characteristics; 70% cellulose yield was extracted successfully from linseed straw fiber using 75% ethanol-toluene at 98 °C for 4 h, 6% NaOH at 75 °C for 30 min, and 6% H2O2 at 90 °C for 120 min.

Comparison of ozone-based AOPs on the removal of organic matter from the secondary biochemical effluent of coking wastewater

ABSTRACT Advanced oxidation processes (AOPs) based on ozone are gaining continuously growing popularity in wastewater treatment. This study explored the treatment of coking wastewater using a combination of ozonation (O3), ultraviolet (UV), and hydrogen peroxide (H2O2) process expressed by % chemical oxygen demand (COD) removal, % total organic carbon (TOC), % UV254, % fluorescence intensity removal and its electrical energy consumption. The obtained results demonstrated that, the combination of O3, UV, and H2O2 which is denoted by O3/UV/H2O2 in this study achieved great success in COD removal (92.08%), TOC removal (78.25%), and reduction of fluorescence intensity (99.82%). Compared with the O3 and O3/UV processes, O3/UV/H2O2 improved the COD removal by approximately 54–69% and 38–51%, respectively. In addition, the energy consumption was reduced by 53–67%. The TOC removal rate in the effluent ranged 71% and 83%, while the UV254 removal rate was up to 90%. The fluorescence spectroscopy showed that the O3/UV/H2O2 combination process reduced the fluorescence intensity by almost 97% within 10 min. Furthermore, the total polycyclic aromatic hydrocarbons (PAHs) concentration in the effluent was less than 10μg/L (removal efficiency > 80%) and the most toxic benzo(a)pyrene (BaP) was less than 0.03 μg/L (0.018μg/L). In addition, the energy consumption of the O3/UV/H2O2 process was 53–67% lower than those of O3 and O3/UV processes. Furthermore, the energy consumption was 80.26 kWh m−3 after 60 min of reaction time when the COD (69.3 mg/L) met the standard discharge. Finally, the O3/UV/H2O2 process could be an effective method for improving the mineralisation of refractory organic matter.

Conversion of agricultural and forestry biomass into bioethanol, water-soluble polysaccharides, and lignin nanoparticles by an integrated phosphoric acid plus hydrogen peroxide process

Conversion of agricultural and forestry biomass into bioethanol, water-soluble polysaccharides, and lignin nanoparticles by an integrated phosphoric acid plus hydrogen peroxide process

The influence of the food factor on the components of the antioxidant protection system in fish

Functional feeding complexes that correct metabolic processes in animal bodies, increasing their productivity and preventing infectious diseases are a new direction in the development of modern feed production. Such feeds, thanks to a set of components, have a wide range of healing effects. We have developed a feed additive consisting of probiotics, adaptogens, vitamins and amino acids. The aim of the work was to study the effect of a new feed additive on the antioxidant system of fish. During the research, it was found that the content of glutathione (GSH) in male fish raised on the background of biologically active feed additive doubled, and in females by more than 30%, and the activity of glutathione-S-transferase also increased. Therefore, on the background of the use of new biologically active feed additive, the resistance of the fish body to free radical and peroxide processes increases.

Degradation of petroleum pollutants in oil-based drilling cuttings using an Fe2+-based Fenton-like advanced oxidation processes.

Oil-based drilling cuttings (OBDC) contain a large amount of total petroleum hydrocarbon (TPH) pollutants, which are hazardous to the environment. In this study, Fe2+-activating hydrogen peroxide (Fe2+/H2O2), peroxymonosulfate (Fe2+/PMS), and peroxydisulfate (Fe2+/PDS) advanced oxidation processes (AOPs) were used to treat OBDC due to the difference in the degradation capacity of TPH caused by the type of free radical generated and effective activation conditions observed for the different oxidants studied. The results showed that the oxidant concentration, Fe2+ dosage, and reaction time in the three AOPs were greatly positively correlated with the TPH removal rate in a certain range. The initial pH value had a significant effect on the Fe2+/H2O2 process, and its TPH removal rate was negatively correlated in the pH range from 3 to 11. However, the Fe2+/PMS and Fe2+/PDS processes only displayed lower TPH removal rates under neutral conditions and tolerated a wider range of pH conditions. The optimal TPH removal rates observed for the Fe2+/H2O2, Fe2+/PMS, and Fe2+/PDS processes were 45.04%, 42.75%, and 44.95%, respectively. Fourier transform infrared spectrometer and gas chromatography-mass spectrometer analysis showed that the alkanes in OBDC could be effectively removed using the three processes studied, and their degradation ability toward straight-chain alkanes was in the order of Fe2+/PMS > Fe2+/PDS > Fe2+/H2O2, among which Fe2+/PMS exhibited the optimal removal effect for aromatic hydrocarbons. Scanning electron microscope, energy dispersive spectroscopy, and X-ray diffraction results showed no significant changes in the elemental and mineral composition of OBDC before and after treatment. Therefore, this study provided a theoretical reference for the effective degradation of TPH pollutants in OBDC.

Identifying the evolution of primary oxidation mechanisms and pollutant degradation routes in the electro-cocatalytic Fenton-like systems

Herein, electro-catalysis (EC) as the electron donor to accelerate the continuable Fe(III)/Fe(II) cycles in different inorganic peroxides (i.e., peroxymonosulfate (PMS), peroxydisulfate (PDS) and hydrogen peroxide (HP)) activation systems were established. These electro-cocatalytic Fenton-like systems exhibited an excellent degradation efficiency of sulfamethoxazole (SMX). A series of analytical and characterization methods including quenching experiments, probe experiments, and electron paramagnetic resonance spectrometry (EPR) were implemented to systematically sort out the source and yield of reactive oxygen species (ROS). A wide kind of ROS including hydroxyl radical (•OH), singlet oxygen (1O2), and sulfate radical (SO4•−), which contributed 38%, 37%, and 24% were produced in EC/Fe(III)/PMS system, respectively. •OH was the dominant ROS in both EC/Fe(III)/PDS and EC/Fe(III)/HP processes. According to the analysis of SMX degradation routes and biotoxicity, abundant degradation pathways were identified in EC/Fe(III)/PMS process and lower environmental impact was achieved in EC/Fe(III)/HP process. The diversiform ROS of EC/Fe(III)/PMS system makes it exhibit greater environmental adaptability in complex water matrixes and excellent low-energy consumption performance in many organic pollutants degradation. Continuous flow treatment experiments proved that the three systems have great sustainability and practical application prospect. This work provides a strong basis for constructing suitable systems to achieve different treatment requirements.

WGCNA Analysis Revealed the Hub Genes Related to Soil Cadmium Stress in Maize Kernel (Zea mays L.).

Soil contamination by heavy metals has become a prevalent topic due to their widespread release from industry, agriculture, and other human activities. Great progress has been made in elucidating the uptake and translocation of cadmium (Cd) accumulation in rice. However, there is still little known about corresponding progress in maize. In the current study, we performed a comparative RNA-Seq-based approach to identify differentially expressed genes (DEGs) of maize immature kernel related to Cd stress. In total, 55, 92, 22, and 542 DEGs responsive to high cadmium concentration soil were identified between XNY22-CHS-8 vs. XNY22-YA-8, XNY22-CHS-24 vs. XNY22-YA-24, XNY27-CHS-8 vs. XNY27-YA-8, and XNY27-CHS-24 vs. XNY27-YA-24, respectively. The weighted gene co-expression network analysis (WGCNA) categorized the 9599 Cd stress-responsive hub genes into 37 different gene network modules. Combining the hub genes and DEGs, we obtained 71 candidate genes. Gene Ontology (GO) enrichment analysis of genes in the greenyellow module in XNY27-YA-24 and connectivity genes of these 71 candidate hub genes showed that the responses to metal ion, inorganic substance, abiotic stimulus, hydrogen peroxide, oxidative stress, stimulus, and other processes were enrichment. Moreover, five candidate genes that were responsive to Cd stress in maize kernel were detected. These results provided the putative key genes and pathways to response to Cd stress in maize kernel, and a useful dataset for unraveling the underlying mechanism of Cd accumulation in maize kernel.

Trace Mn(II)-catalyzed periodate oxidation of organic contaminants not relying on any transient reactive species: The substrate-dependent dual roles of in-situ formed colloidal MnO2

Traditional advanced oxidation processes (AOPs) generally suffer from the inevitable deactivation of catalysts and the ineffective consumption of transient reactive species (TRSs) that compromise the efficiency in destructing aqueous contaminants. Herein, it was interestingly found that trace Mn(II) could robustly catalyze the oxidation of organic contaminants by periodate (PI), with the performance was much better than the representative TRSs-dominated AOPs (i.e., the Fe(II)-activated hydrogen peroxide, peroxymonosulfate (PMS), peroxydisulfate and PI processes). Multiple lines of evidence excluded the oxidative contributions of TRSs, instead the stoichiometric formation of colloidal MnO2 via the condensation of di-μ-oxo-bridged Mn(IV) cluster was confirmed by UV-vis, X-ray absorption near edge structure spectroscopy and density functional theory calculation. Dependent on the structure of substrate, MnO2 colloids solely or simultaneously served as oxidant and catalyst for the enhanced treatment performance. Benefiting from the non-TRSs-involved oxidation strategy and the catalytic effects of Mn species, the trace-Mn(II)/PI process even outperformed the Co(II)-activated PMS counterpart (i.e., one of the most efficient AOPs known at present) on oxidant utilization efficiency. This study not only elucidated the roles of Mn(II) and colloidal MnO2 in PI-mediated contaminant degradation, but also signified the superiority of trace catalyst-assisted process without TRSs involvement in avoiding undesired side reactions and maximizing oxidation efficiency.

Synergistic improvement of short-chain fatty acid production from waste activated sludge via anaerobic fermentation by combined plasma-calcium peroxide process

In this study, the combination of dielectric barrier discharge plasma (DBD) with calcium peroxide (CaO2) achieved significant synergistic effects in promoting hydrolysis of waste activated sludge (WAS) and short-chain fatty acid (SCFA) production during anaerobic fermentation. Compared with the control, DBD/CaO2 pretreatment increased SCFA production by 116 %, acetic acid ratio by 39 %, and sludge reduction by 30 % under the optimal conditions (discharge power = 76.5 W, CaO2 dosage = 0.05 g/g VSS). Mechanism investigations elucidated that DBD/CaO2 enhanced the generation of •OH, 1O2, and •O2−, synergistically promoted decomposing extracellular polymeric substances (EPS), lysing cells, releasing biodegradable substances, and enhancing acetic acid-enriched SCFA accumulation from fermentation. Meanwhile, Illumina MiSeq sequencing analysis revealed that the enrichment of hydrolytic and SCFAs-forming bacteria and the decrease in SCFAs-consuming bacteria by DBD/CaO2 treatment also contributed. This work provides an effective method to boost the SCFA production from WAS fermentation.

Wastewater Treatment Using a Photoelectrochemical Oxidation Process for the Coffee Processing Industry Optimization of Chemical Oxygen Demand (COD) Removal Using Response Surface Methodology

The elimination of organic compounds in coffee processing effluent utilizing electrochemical oxidation (ECO) as well as a combination of electrochemical oxidation (ECO) and ultraviolet and hydrogen peroxide (UV/H2O2) was explored. Then, the percentage reduction of chemical oxygen demand (COD) was investigated. The effect of different experimental factors such as solution pH, sodium chloride (NaCl) concentration, calcium chloride (CaCl2) concentration, electric current, electrolysis duration, and hydrogen peroxide dosage on the percent removal efficiency of the hybrid electrochemical oxidation (ECO) with the ultraviolet and hydrogen peroxide (UV/H2O2) process has been investigated. The response surface methodology (RSM) based on central composite design (CCD) was used to organize the trial runs and optimize the results. The hybrid electrochemical oxidation (ECO) with the ultraviolet and hydrogen peroxide (UV/H2O2) process removed 99.61% of the chemical oxygen demand (COD) with a low power usage of 1.12 kWh/m3 compared to the other procedures, according to the experimental data analysis. These findings were obtained with a pH of 7, a current of 0.40 A, 1.5 g of CaCl2, and a total electrolysis period of 40 minutes. When it came to eliminating organic compounds from coffee manufacturing effluent, CaCl2 outperformed NaCl. Analysis of variance (ANOVA) with 95% confidence limits was used to examine the significance of independent variables and their interactions.