Peroxide Dosage Research Articles

Sonolysis-ozonation and peroxidation method for removal of atenolol and amoxicillin in wastewater

Pharmaceutical compounds represent a significant challenge as water pollutants due to their persistence and adverse impacts on both the environment and human health. In the present study, the degradation of two pharmaceuticals- atenolol and amoxicillin was assessed in three advanced oxidation processes (AOPs), namely sonolysis, ozonation, and electrochemical peroxidation (ECP) under varying operational conditions using sewage as water matrix. The degradation of atenolol and amoxicillin was found to be over 95% at 1350W, contact time of 15min and pH of 3 during sonolysis. Ozonation proved very effective in the removal of both pharmaceuticals (>95%) in a short contact time of 30seconds using 0.32g/L-min ozone dose at pH 9. The removal of pharmaceuticals was highest at pH 9 compared to pH 4, and an ozone dosage of 0.21g/L-min was found to be adequate for achieving good degradation for both pharmaceuticals (>85%). In ECP, the maximum removal obtained for atenolol and amoxicillin was 94% and 91%, respectively, by using a current intensity of 10mA/cm2 and a hydrogen peroxide dose of 3mM. Ozonation rapidly degraded (>95%) atenolol and amoxicillin in just 30seconds, showcasing its superior performance.

Treatment of Organic Pollutant by Advanced Oxidation Processes

The investigation involved the oxidation of urea (UR) in a batch reactor, employing Fenton's reagent. Various parameters, namely reaction time, pH level, ferrous ion dose, and hydrogen peroxide dose, were scrutinized. The reaction time spanned from 30 minutes to 3 hours, revealing a notably positive impact. An optimal pH of 3 was identified for the medium. The concentrations of ferrous ions ranged from 0.2 g/l to 0.53 g/l, with hydrogen peroxide levels ranging from 1 g/l to 2.65 g/l. The impact of hydrogen peroxide was notably significant at a ferrous ion concentration of 0.3 g/l and a pH of 3. Evaluating urea removal efficiency through chemical oxygen demand (COD) calculations showed a maximum efficiency of 86.8%, with a minimum ammonia yield of 6%. Overall, the outcomes underscored the efficacy of the Fenton process in urea treatment.

Stress-Induced Production of Bioactive Oxylipins in Marine Microalgae.

Microalgae, stemming from a complex evolutionary lineage, possess a metabolic composition influenced by their evolutionary journey. They have the capacity to generate diverse polyunsaturated fatty acids (PUFAs), akin to those found in terrestrial plants and oily fish. Also, because of their numerous double bonds, these metabolic compounds are prone to oxidation processes, leading to the creation of valuable bioactive molecules called oxylipins. Moreover, owing to their adaptability across various environments, microalgae offer an intriguing avenue for biosynthesizing these compounds. Thus, modifying the culture conditions could potentially impact the profiles of oxylipins. Indeed, the accumulation of oxylipins in microalgae is subject to the influence of growth conditions, nutrient availability, and stressors, and adjusting these factors can enhance their production in microalgae culture. Consequently, the present study scrutinized the LC-MS/MS profiles of oxylipins from three marine microalgae species (two Haptagophytes and one Chlorophyte) cultivated in 1 L of photobioreactors under varying stress-inducing conditions, such as the introduction of H2O2, EtOAc, and NaCl, during their exponential growth phase. Approximately 50 oxylipins were identified, exhibiting different concentrations depending on the species and growth circumstances. This research suggests that microalgae metabolisms can be steered toward the production of bioactive oxylipins through modifications in the culture conditions. In this instance, the application of a low dose of hydrogen peroxide to Mi 124 appears to stimulate the production of nonenzymatic oxylipins. For Mi136, it is the application of salt stress that seems to increase the overall production of oxylipins. In the case of Mi 168, either a low concentration of H2O2 or a high concentration of AcOEt appears to have this effect.

Preparation of magnetite nanoparticles and their application in the removal of methylene blue dye from wastewater

Wastewater is discharged in large amounts from different industries; thus, wastewater treatment is currently one of the main concerns, advanced oxidation is a promising technique for wastewater treatment. This research aims to synthesize magnetite nanoparticles and study their application in wastewater treatment via adsorption and advanced oxidation processes. Magnetite nanoparticles were synthesized via coprecipitation technique between ferric and ferrous sulfate at a molar ratio of 2:1. The prepared sample was characterized using FTIR, XRD, TEM, BET surface area, zeta potential, VSM, and UV‒visible spectroscopy. XRD confirmed the formation of a single face-centered cubic (FCC) spinel structure of Fe3O4. TEM revealed an average particle size of 29.2 nm and a BET surface area of 70.1 m2 g−1. UV‒visible spectroscopy revealed that the UV–visible peak of the sample was obtained at 410 nm. VSM confirmed the attraction of the sample to a magnet with a magnetization of 60 (emu/g). The removal efficiency of methylene blue was studied using adsorption and advanced oxidation methods. For adsorption, the studied parameters were dye concentration 2–10 ppm, 3–10 pH, and 50:300 mg Fe3O4/L. For advanced oxidation, peroxide was used with nanomagnetite as a catalyst, and the studied parameters were pH 2–11, magnetite dose 20–200 PPM, and peroxide dose 500–2000 PPM. The removal efficiency by adsorption reached 95.11% by adding 50 mg of Fe3O4/L and 10 ppm dye conc at 6.5 pH; on the other hand, in advanced oxidation, it reached 98.5% by adding 110 PPM magnetite and 2000 ppm H2O2 at pH 11. The magnetite nanoparticles were reused for ten cycles of advanced oxidation, for a 10% reduction in removal efficiency at the tenth cycle.

Microplasma-assisted construction of cross-linked network hierarchical structure of NiMoO4 nanorods @NiCo-LDH nanosheets for electrochemical sensing of non-enzymatic H2O2 in food

The accumulation of small doses of hydrogen peroxide (H2O2) into food can cause many diseases in the human body, and it is urgent to develop efficient detection methods of H2O2. Herein, the hierarchical structure composite of NiCo-LDH nanosheets crosslinked NiMoO4 nanorods was grown in situ on carbon cloth (NiMoO4 NRs@NiCo-LDH NSs/CC) by micro-plasma assisted hydrothermal method. Thanks to the synergistic effect of three metals and (NiMoO4 NRs@NiCo-LDH NSs/CC) provided by nanorods/nanosheets hierarchical structure, NiMoO4 NRs@NiCo-LDH NSs/CC exposes more active sites and achieves rapid electron transfer. The H2O2 electrochemical sensor was constructed as the working electrode with a linear range of 1 μmol L−1 to 9.0 mmol L−1 and detection limit of 112 nmol L−1. In addition, the sensor has been successfully applied to the detection of H2O2 in food samples, the recovery rate is 95.2%–106.62%, RSD < 4.89%.

Innovating Ferro-sonication approach for extracting microplastics from wastewater

For accurate and reliable analysis of microplastics (MPs) in wastewater (WW), it is imperative to comprehend the significance of pre-treating WW before analysis. The suspended solids (SS) in the matrix tend to adhere to the MPs during filtration, which interferes with the detection of the MPs. In this regard, the present study aims to develop and optimize a pretreatment method to improve the extraction efficiency of MPs from WW by reducing the SS. A combination of the Fenton reaction and ultrasonication, ferro-sonication (Fe-UlS), was proposed to digest and eliminate the SS from WW. This hybrid pretreatment, Fe-UlS, was optimized for ultrasonication amplitude, treatment time, and hydrogen peroxide dose using response surface methodology (RSM) with a Box-Behnken design, achieving a desirability of 0.984. The optimum conditions for the Fe-UlS, such as the (1:1) Fenton reagent ratio (0.05 M FeSO4: 30 % H2O2), ultrasonication amplitude (31 %), and total process time (30 min) were found to be statistically significant (p < 0.05). The developed method was then employed for the extraction of spiked polyethylene (PE), polypropylene (PP) and polyethylene terephthalate (PET) MPs in real WW and found efficient in removing 83 % of the TSS present in the primary influent were in 30 min at a temperature of 45 °C. Also, the method did not affect the physio-chemical characteristics of the MPs; however, the thermal analysis of PE and PP MPs showed a statistically significant decrease in the melting temperature, as proven by paired t-test analysis. Further, a non-targeted liquid chromatography-mass spectrometry (LC-MS) analysis proved that Fe-UlS is a stable process, as it did not cause any leaching of MPs under the optimum pretreatment conditions. Finally, Laser Direct-Infrared Imaging (LD-IR) analysis was conducted to validate the developed Fe-UlS pretreatment approach for MP analysis in real WW. About 3434 MPs were detected in 100 mL of WW primary influent, within the size range of 9 to 500 μm. This hybrid pretreatment approach not only streamlines WW sample processing but also reduces the required concentration of Fenton reagent and processing time, yielding accurate and reliable results for monitoring MPs in WW.

An effective algaecide for the targeted destruction of Karenia brevis

We address the targeted destruction of Karenia brevis using the algaecide calcium peroxide, in tandem with the flocculation and sinking of the species. The specific aspect of the approach is the incorporation of the algaecide within the floc to rapidly kill K. brevis, thus minimizing escape of cells from the floc and reentry to the water column. CaO₂ gradually produces H₂O₂, which diffuses through cell membranes and induces oxidative stress, leading to cell death via excessive reactive oxygen species (ROS) formation. The effect of varying doses of calcium peroxide on K. brevis cells was measured with pulse amplitude modulated fluorometry and indicated that doses as low as 30 mg/L when integrated into flocs are effective in suppressing photosynthesis. Cell viability assays also indicate that such low levels are sufficient to cause cell death in a 3-6 hour time period. Thus, the proposed technology involving the incorporation of calcium peroxide in a cationic flocculating agent (polyaluminum chloride, PAC) leads to an inexpensive and scalable technology to mitigate harmful algal blooms of K. brevis.

Strong Magnetic p-n Heterojunction Fe3O4-FeWO4 for Photo-Fenton Degradation of Tetracycline Hydrochloride

With the abuse of antibiotics, its pollution poses an increasing threat to the environment and human health. Effective degradation of organic pollutants in water bodies is urgent. Compared to traditional treatment methods, advanced oxidation processes that have developed rapidly in recent years are more environmentally friendly, efficient and applicable to a wider range of organic compounds. FeWO4 was used in this study as the iron-based semiconductor material to modify and optimize the material design. Fe3O4/FeWO4 composites were prepared by a two-step hydrothermal method. The crystal structure, surface morphology, electrochemical properties and separability of the composite semiconductor were analyzed by XRD, XPS, UV-vis, SEM, EDS and Mott-Schottky. The results showed that, when the initial contaminant concentration was 30 mg/L, the initial solution pH was 4, the dosage of the catalyst was 25 mg and the dosage of hydrogen peroxide was 30 μL, the degradation efficiency of tetracycline hydrochloride (TCH) could reach 91% within 60 min, which was significantly improved compared to the performance of the single semiconductors Fe3O4 and FeWO4. In addition, the catalyst prepared in this experiment can be easily recovered by magnetic separation technology in practical application, which will not affect the turbidity of water while reducing the cost of catalyst separation and recovery.

Exploring the role of hydrogen peroxide dosage strategies in the photo-Fenton process: Scaling from lab-scale to pilot plant solar reactor

This study aims to investigate the role of hydrogen peroxide (HP) continuous dosage in removing Paracetamol (PCT) from different water matrices using the solar photo-Fenton process. Different parameters in the HP dosage strategies (initial HP pulse, dosing time, and HP concentration) were systematically analysed to assess their impacts on pollutant removal (XPCT), oxidant specific consumption (YHP/PCTt), and toxicity levels (I(%)). The analysis involved various water matrices (ultrapure water UW, groundwater GW, anion matrix AW, and synthetic pharmaceutical wastewater IW0.01 or IW0.1), which were firstly treated in a laboratory reactor and subsequently scaled up to a solar prototype. After laboratory testing, the most effective reaction configuration (maximum XPCT and YHP/PCTt close to the stoichiometric one) was chosen as the starting point for scaling up the reaction system. Using the solar reactor setup, complete PCT conversion was achieved within just 60 min of reaction time (UW matrix). However, under IW0.1 condition and employing the same HP dosing strategy, a XPCT of 95.4 % was attained but at 180 min of reaction, highlighting the significant influence of the real matrix. Additionally, the I(%) remained high towards the end of the reaction (close to 60 %), attributed to the presence of hydroquinone in the system, demanding longer reaction times to completely reduce the toxicity when working with industrial wastewater. This comprehensive approach aims to close the gap between lab results and practical applications, offering crucial insights to address pharmaceutical wastewater pollution.

Highly efficient novel heterojunction catalyst in the elimination of antibiotics under the photo-Fenton-like process

The antibiotic residues in aquatic environments pose severe environmental concerns due to their ability to mediate antibiotic resistance genes through the microbes. The prime concern is the efficient and sustainable treatment of these residual antibiotics from waterbodies. The study aims to derive a novel bimetallic heterogeneous nano-catalyst, Ag0/Fe0/OSBC, by simple impregnation method in a greener process that involves natural phytochemicals of Artocarpus heterophyllus Lam leaves. The phytochemicals readily synthesize in in-situ Fe and Ag nanoparticles. Various advanced analytical tools reasonably characterize the synthesized materials. The study evaluates insights into heterojunction catalyst efficiency in degrading the sulfamethoxazole (SMX) and amoxicillin (AMX) under the advanced oxidation process. The photo-Fenton-like process assesses the elimination efficacy of the catalyst under dark, LED-VIS, and UV-A light conditions. The optimized batch operation parameters include solution pH 3.0, hydrogen peroxide dosage 0.10 mL/L (SMX); 0.25 mL/L (AMX), catalyst dosage 250.0 mg/L (SMX); 150.0 mg/L (AMX), and pollutant concentration of 2.0 mg/L. The parametric investigations offer insights into the degradation process's mechanisms and, the removal efficacy achieves 82.6 % and 92.8 %, respectively, for SMX and AMX. The process of mineralization using UV-A light achieves 68.0 % and 70.4 % for SMX and AMX, respectively. Minimal corrosion of Fe from the catalyst shows the catalyst's enhanced applicability and stability. The repeated cycles enabled a sustainable catalytic process, and real implications showed a higher selectivity of the process.

Enhancing sulfide and methane control in sewers: Unveiling the impact and mechanisms of free nitrous acid pre-exposure coupled with calcium peroxide dosing

Although biocides have proven highly efficient in controlling hazardous emissions and mitigating organic carbon loss in sewers, the resistance of biofilm and extracellular polymeric substances (EPS) to biocides has emerged as a significant impediment to addressing these challenges. In this study, a promising strategy of calcium peroxide (CaO2) dosing assisted by free nitrous acid (FNA) pre-exposure overcame these limitations. Prior to a 6-hour exposure to 0.1 % (w/v) CaO2, a 2-hour pre-exposure to a low dose of 0.26 mg-N/L FNA demonstrated a significant enhancement in sulfide and methane control efficiency by 267.14 % and 390.47 %, respectively, compared to direct exposure to 0.2 % CaO2 for 12 h. Moreover, there was a notable increase of 40.05 % in soluble COD level in the effluent. FT-IR and XPS analyses discovered the disruption, migration, and dissolution of biofilm, accompanied by a substantial increase in membrane permeability (up to 2.89 folds). Additional analysis revealed that the synergistic effects of various reactive nitrogen/oxygen species destabilized the structure of EPS, e.g., declining total EPS yield, disintegrating humic acid-like and tryptophan- and protein-like substances, reducing hydrogen bond in β-sheet of proteins. Further down-regulation of node genes associated with sulfidogenesis and methanogenesis verified the toxic mechanism at the genetic level. Microbial community analysis revealed a significant reduction in the abundance of sulfate-reducing bacteria and methanogenic archaea, leading to an extended recovery period for sulfide and methane production in sewer biofilm. This study provides an effective strategy and in-depth mechanisms for biofilm control, applicable beyond sewer biofilm.

Oczyszczanie ścieków z wytłoczyn z oliwek poprzez elektrokoagulację peroksydacyjną z wykorzystaniem arkuszy aluminiowych

The extraction of olive pomace oil is a significant aspect of the edible oil industry in Mediterranean regions where olives are widely cultivated. The resulting wastewater generated from this industry is known to harbor pollutants, including residual solvents, oils, and chemicals from the refining process, that can have adverse effects on the environment and public health. Peroxy-electrocoagulation (PEC) is a method that can be used to treat wastewater from the olive pomace oil extraction industry. The purpose of the work was to reduce the concentration of pollutants in the effluent through the use of PEC with aluminum electrodes as a method of treatment. The Box-Behnken Design was used to study the relationship between hydrogen peroxide dosage (10, 20, and 30 g L-1), electric current density (5, 20 and 35 mA cm-2), and the initial pH (2.5, 3.5, and 4.5), in the PEC process, and the removal of chemical oxygen demand (COD) and total phenolic compounds (TPh). The highest removal was obtained with hydrogen peroxide dosage of 30 g L-1, and 20 mA cm-2, and with 29% of TPh removal at pH 2.5, and with 84% COD removal at pH 4.5. The procedure removed an average of 22% COD and 82% TPh. The concentration of hydrogen peroxide was one of the most significant factors in the process. Pre-treatment with other techniques is necessary to reduce harmful elements in the effluent before undergoing biological treatment.

Obróbka dla przemysłu ekstrakcji oliwy z oliwek poprzez zastosowanie peroksy-elektroutleniania

This study aimed to assess the effectiveness of peroxy-electrooxidation (PEO) for treating wastewater from the olive pomace oil extraction industry. The response surface methodology was utilized to optimize the efficiency of the PEO process under varying conditions of electrolysis time, current density, and hydrogen peroxide (H2O2) dosage. Appling graphite/aluminum sheets as cathode/anode in the treatment process showed that the concentration of H2O2 directly affected the efficiency of total phenolic compounds (TPh) removal. It was observed that at an H2O2 concentration of 15 g L-1, the removal efficiency was less than 80%. The removal of chemical oxygen demand (COD) is mainly influenced by the dosage of H2O2 and the reaction time. The experiments conducted on the PEO processes with graphite/iron sheets showed that the highest removal of TPh was achieved with an H2O2 dosage of 30 g L-1 and an intermediate reaction time of 30 minutes. Current density also had an impact on TPh removal. Regarding COD removal, the results showed that the highest removal rates were attained with increased H2O2 concentrations, but reaction time was a positive factor, with better results obtained with 30 and 50 minutes. The PEO is recommended as a pre-treatment for TPh removal but not for COD and other treatment processes should be evaluated.

Removal of antibiotic residue from aqueous solution by advanced oxidation process

Advanced oxidation processes are low-cost, highly efficient, and eco-friendly technologies in the removal of organic pollutants in wastewater using hydroxyl radicals for oxidation. Hydroxyl radicals possess high oxidation potential and can react with organic compounds, resulting in the complete mineralization of these compounds into carbon dioxide, water, and inorganic salt or their conversion into other compounds. The present investigation deals with the removal of tetracycline from water using simulated ultraviolet radiation and hydrogen peroxide, assessing the effect of operational parameters like the solution's initial pH, retention time, hydrogen peroxide dosage in terms of chemical oxygen demand (COD) removal from the standard aqueous solution of tetracycline. Results indicate that alkaline conditions and larger hydrogen peroxide dosage negatively affect the degradation. The removal efficiency of 68 % was achieved at 150 min of batch reaction under optimum conditions: pH = 4, and a dose of hydrogen peroxide of 0.3 ml per 100 ml of the solution to be treated. At optimum conditions, LC-MS/MS (liquid chromatography tandem mass spectrometry) analysis results showed a reduction in initial concentration of aqueous solution of tetracycline. Photocatalytic degradation followed pseudo-first-order kinetics with the rate constant (k) of 0.0061 min-1. Photocatalysis based on hydrogen peroxide is effective in the degradation of tetracycline in an aqueous solution and can be applied as a pretreatment of hospital wastewater containing tetracycline residues.

Decolorization enhancement of basic fuchsin by UV/H2O2 process: optimization and modeling using Box Behnken design

The present work deals with the optimization of basic fuchsin dye removal from an aqueous solution using the ultraviolet UV/H2O2 process. Response Surface Modeling (RSM) based on Box-Behnken experimental design (BBD) was applied as a tool for the optimization of operating conditions such as initial dye concentration (10–50 ppm), hydrogen peroxide dosage (H2O2) (10–20 mM/L) and irradiation time (60–180 min), at pH = 7.4 under ultra-violet irradiation (254 nm and 25 W intensity). Chemical oxygen demand (COD abatement) was used as a response variable. The Box–Behnken Design can be employed to develop a mathematical model for predicting UV/H2O2 performance for COD abatement. COD abatement is sensitive to the concentration of hydrogen peroxide and irradiation time. Statistical analyses indicate a high correlation between observed and predicted values (R2 > 0.98). In the BBD predictions, the optimal conditions in the UV/H2O2 process for removing 99.3% of COD were found to be low levels of pollutant concentration (10 ppm), a high concentration of hydrogen peroxide dosage (20 mM/L), and an irradiation time of 80 min.

Municipal sewage sludge dewatering performance enhancement by ultrasonic cavitation and advanced oxidation: A case study.

The number of published literature on the effect of ultrasonic cavitation and advanced oxidation pretreatment on the dewatering performance of anaerobically digested sludge is very limited. This study aims at determining the optimum operating conditions of large-scale filtering centrifuges in wastewater treatment plants. The optimum dose of hydrogen peroxide, ultrasonic power, ultrasonic duration, ultrasonic pulse and particle size distribution for improved dewatering performance were determined in this study. In addition, shear stress-shear rate and viscosity-shear rate rheograms were developed to show the rheological flow properties for varying ultrasonic power and treatment duration. Optimum sonication power, time, pulse and amplitude were determined to be 14 W, 1 min, 55/5 and 20%, respectively. At a pH of 6.8, the optimum concentration of hydrogen peroxide was found to be 43.5 g/L. The optimum hydrogen peroxide dose in the combined conditioning experiments was determined to be 500 mg/L at a pH of 3. Under these optimum conditions, capillary suction time was reduced significantly by 71.1%. This study helps to reduce polymer consumption and provides the optimum pretreatment and dewatering operating conditions, and better monitoring and control in the dewatering unit has significant impact in the overall economy of wastewater treatment plants.

Effect of Calcium Peroxide on the Food Waste Composting Process

Aerobic composting acknowledged as a crucial technology in the management of food waste, offers a potential approach to sustainable production practices by producing top-notch organic fertilizers and soil conditioners. Nevertheless, the natural process of composting contributes to environmental pollution by releasing carbon dioxide (CO2) and methane (CH4) into the atmosphere. This study examines the effectiveness of adding calcium peroxide to the composting process to improve the availability of oxygen, reduce CO2 emissions, and enhance the quality of the final products. The study involved conducting experimental trials using different doses of calcium peroxide (5%, 10%, 15%, and 20%) to evaluate its effect on reducing CO2 levels. The results demonstrate a substantial decrease in CO2 emissions, where concentrations of 20% lead to a reduction of 36.82%while in 5%, 10%, and 15% the reductions were 19.15%,26.36%, and 36.32%, respectively. In addition, the inclusion of calcium peroxide raises the pH of food waste samples and introduces calcium ions (Ca2+) into the end product. The results emphasize the significance of dealing with carbon emissions in composting procedures to adhere to Sustainable Development Goals 12 (responsible consumption and production) and 13 (climate action), thus progressing towards more sustainable waste management techniques.

Enhanced multi-metals stabilization: Synergistic insights from hydroxyapatite and peroxide dosing strategies

Sediment contamination by heavy metals is a pressing environmental concern. While in situ metal stabilization techniques have shown promise, a great challenge remains in the simultaneous immobilization of multi-metals co-existing in contaminated sediments. This study aims to address this challenge by developing a practical method for stabilizing multi-metals by hydroxyapatite and calcium peroxide (HAP/CaO2) dosing strategies. Results showed that dosing 15.12 g of HAP/CaO2 at a ratio of 3:1 effectively transformed labile metals into stable fractions, reaching reaction kinetic equilibrium within one month with a pseudo-second-order kinetic (R2 > 0.98). The stable fractions of Nickel (Ni), Chromium (Cr), and lead (Pb) increased by approximately 16.9 %, 26.7 %, and 21.9 %, respectively, reducing heavy metal mobility and ensuring leachable concentrations complied with the stringent environmental Class I standard. Mechanistic analysis indicated that HAP played a crucial role in Pb stabilization, exhibiting a high rate of 0.0176 d−1, while Cr and Ni stabilization primarily occurred through the formation of hydroxide precipitates, as well as the slowly elevated pH (>8.5). Importantly, the proposed strategy poses a minimal environmental risk to benthic organisms exhibits almost negligible toxicity towards Vibrio fischeri and the Chironomus riparius, and saves about 71 % of costs compared to kaolinite. These advantages suggest the feasibility of HAP/CaO2 dosing strategies in multi-metal stabilization in contaminated sediments.

Efficient H2O2 -sonochemical treatment of Penicillin G in water: Optimization, DI-HRMS ultra-trace by-products analysis, and degradation pathways

Due to widespread usage of antibiotics, the possibility of surface and groundwater contamination with such pollutants has significantly increased over the years as such antibiotics have been widely reported in water bodies. This study reports on the elimination of toxic antibiotic Penicillin G (PG) from wastewaters sources via the sonochemical process in the presence of hydrogen peroxide (H2O2) as well as to identify the degradation by-products. The effect of initial pH, pollutant dosage and presence of hydrogen peroxide on the degradability was examined. Response Surface Methodology (RSM) was used to model the sonochemical process with high correlation of (R2= 0.9784) and predictions agreed well with the experimental results. Box-Behnken Design (BBD) and RSM equations were used to determine the optimal values of experimental conditions for the PG degradation at the optimum conditions: PG dose of 20 mgL−1, pH 3.4 and hydrogen peroxide (H2O2) concentration of 600 mgL−1. Under the optimized conditions, removal efficiency reached 97% and by-products formed during sonochemical degradation were identified via QuEChERS method (Quick, Easy, Cheap, Effective, Rugged, and Safe), while the pre-concentration by evaporation was followed by the direct infusion-high resolution mass spectrometry technique (DI-HRMS). This is the first study to report a detailed investigation on PG degradation products under the sonochemical treatment combined with QuEChERS method to DI-HRMS techniques. Such advanced methods allowed us to determine the analyte substance found in water at low concentrations (ng L−1). The seven by-products have been detected where two possible degradation pathways were proposed with a resulting total elimination of PG.

Removal of molybdenum by TBP-TRPO extraction in sodium isopolytungstate solution

A new process was proposed for extracting molybdenum from tungsten solutions in acidic tungsten-molybdenum mixed solution. The extraction ratio of molybdenum reached 70 % and the tungsten-molybdenum separation factors reached 400 with the hydrogen peroxide dosage of nH2O2/n(Mo) = 2 (nH2O2/n(W + Mo) = 0.3) for the molybdenum-containing isopolytungstate sodium solution. The experimental conditions resulted in the yield of only 20 % of the traditional method (nH2O2/n(W + Mo) = 1.5–2). The organic phases consisted of 2 % TRPO and 60 % TBP. The saturated extraction capacity of molybdenum was found to be 10 g/L. The solution of 0.3 mol/L sodium bicarbonate was used as the stripping agent. With the temperature of 25 ℃, stripping time of 6 min, and the phase ratio of (O/A)2, the stripping ratio of molybdenum was 90 % and that of tungsten was 70 %. The extraction mechanism of TBP-TRPO and the hydrogen peroxide coordination were analyzed using Raman and infrared analyses. The process has a high industrial potential due to its low hydrogen peroxide dosage, high molybdenum extraction ratio, high separation factor, and low cost.