Aluminum-based ozone catalysts prepared by mixing method: Characteristics, performance and carbon emissions.

Green and low carbon is an essential direction for the development of water treatment technology. Ozone catalysts prepared by the mixing method have advantages in terms of energy consumption and CO2 emissions, but are considered to be insufficient in catalytic efficiency and stability. In this paper, an Mn-Cu-Ce/Al2O3 (MCCA) catalyst was prepared by optimizing the preparation conditions of the mixing method and the types and ratios of active components. Taking petrochemical secondary effluent (PCSE) as the treatment object, the performance of the catalyst and the carbon emission in the preparation process were studied; and compared with the impregnation method. Results showed that compared with catalysts loaded with other components, the MCCA had a higher removal efficiency for TOC (43.04%) and COD (53.18%), which was basically equivalent to the impregnation method, and the treated effluent reached the expected concentration. MCCA promoted the decomposition rate of O3 by ten times, and the main active species generated were found to be •OH and 1O. Similar to the catalytic ozonation by the catalyst prepared by the impregnation method, the adsorption sites and surface hydroxyl groups on the MCCA surface play a significant role in the degradation of pollutants. However, the carbon emission in the catalyst preparation process of the mixing method was 418.68 kg/ton, which was only 44% of the impregnation method (949.67 kg/ton). Under the global low-carbon transition, this study shows that the mixing method aligns more with the concept of green, clean, and efficient ozone catalyst preparation.

Abatement of pesticides residues in commercial farm soils by combined ozonation-solarization treatment.

The widespread use of pesticides against agricultural pest and diseases introduces these pollutants and their transformation products into soils. The toxicity and permanence of these substances make it necessary for the development of remediation strategies in order to mitigate contamination and to further protect consumers. This work was aimed to evaluate the applicability of ozonation-solarization technology in the degradation of pesticide residues in commercial farm soils. The trial was conducted in two exploitations devoted during decades to tomato cultivation under greenhouse and net systems. Treatments were carried out using a pipping network (both superficial and sub-superficial) that delivered ozone in gaseous state after covering the soil with gas-tight plastic film to avoid ozone leaks to atmosphere. Control soil treatments, without ozone exposure, were also conducted. After 40 days of treatment, mean degradation percentages of about 55-61% for both cultivation systems were obtained, when the reduction of these pollutants in the control soils was about 8-15%. Ozonation-solarization impact was also assessed by changes on soil physical-chemical properties. Results suggest that ozonation in combination with solarization technique could be considered as a feasible approach for the remediation of pesticide-polluted farm soils.

Degradation characteristics of refractory organic matter in naproxen pharmaceutical secondary effluent using vacuum ultraviolet-ozone treatment.

Vacuum ultraviolet-ozone (VUV-O3) treatment was found to be superior to ultraviolet-ozone (UV-O3) treatment in terms of ozone utilization and hydroxyl radicals (·OH) generation when used to treat the secondary effluent (SE) from a naproxen pharmaceutical plant. VUV-O3 treatment was beneficial in terms of decolorization (100%), chemical oxygen demand removal (43.29%), and total organic carbon removal (54.81%). The VUV-O3 process was applicable over a wide pH range, and the presence of various anions had no significant influence on the oxidation efficiency. After treatment, the genotoxicity, unsaturation degree, and polarity of the SE decreased. In addition, the oxidation sensitivities of the fluorescent organic compounds were ranked as follows: humic acid-like > tyrosine-like > fulvic acid-like > tryptophan-like Moreover, the VUV-O3 process effectively converted refractory organic matter (molecular weights, MW > 2000 Da) into short-chain molecules with low MWs. The removal efficiency of dissolved organic matter (DOM) was 63.27%, and 77.27% of the DOM was found to be reactive to VUV-O3 oxidation. The unsaturation, polarity, and compositional complexity of the DOM decreased after VUV-O3 treatment. Finally, it was deduced that the direct O3 oxidation,·OH, O2·- and 1O2 played a role in the VUV-O3 oxidation process.

Remediation of pesticide residues using ozone: A comprehensive overview.

Pesticide residues historically represent a severe threat to public health and the environment. Several species worldwide are still in danger from pesticide residues, despite efforts to mitigate the adverse health effects of these pollutants. As agricultural output has increased and scientific understanding has advanced, new methods have emerged for degrading pesticide traces. The remarkable effectiveness of ozone as a broad-spectrum disinfectant and its potential to destroy pesticide residues have led to its widespread use as a residue-free method for improving soil quality, disinfecting food, and treating water, among other benefits. Ozone is cheap to manufacture, making it an affordable option for treating harmful pesticide residues. Its capacity to degrade pesticides without negatively impacting the environment has increased its adoption as a tool for cleaning up after pesticide use. This review extensively provides an overview of ozonation for pesticide residues removal in different settings and applications. Ozone treatment of pesticide residues in the soil, water and food is effective in removing pesticides residues. We highlight recent advances in methods of removing pesticide residues. We discuss several challenges related to the ozone treatment of pesticide residues. Whether used alone or in conjunction with other processes, ozone is highly effective at removing pesticide residues from the environment. Therefore, we recommend this holistic and environmentally friendly strategy to reduce pesticide residues.

Development of a full-scale wastewater treatment plant for licorice root processing factories: A hybrid biodegradation-lime-alum-ozonation process.

Liquorice is a perennial legume that grows principally in Asia, the Middle East and some parts of Europe. The sweet root extract is mainly used in the pharmaceutical, food and confectionary industries. It contains 400 compounds, including triterpene saponins and flavonoids, which are responsible for liquorice's bioactivities. The wastewater (WW) arising from the processing of liquorice can have negative environmental effects and must be treated before being discharged into the environment. Different WW treatment solutions are available. In the last years, increasing attention has been paid to the environmental sustainability of wastewater treatment plants (WWTPs). The present article discusses a hybrid biological (anaerobic-aerobic) and post-biological (lime-alum-ozone) WWTP, designed to treat 105 m3/day complex liquorice root extract WW for agricultural purposes. The influent chemical oxygen demand (COD) and biological oxygen demand (BOD5) were found to be 6000-8000 mg/L and 2420-3246 mg/L, respectively. With a biological hydraulic retention time of 8.2 days and no addition of extra nutrients, the WWTP reached a stable condition after 5 months. Over the course of 16 months, its highly efficient biological treatment reduced COD, BOD5, total suspended solids (TSS), phosphate, ammonium, nitrite, nitrate and turbidity by 86-98 %. However, the WW's colour proved resilient: only 68 % of the colour was removed by the biological treatment, necessitating a combination of biodegradation-lime-alum-ozonation processes in order to reach 98 % efficiency. Thus, this study reveals that liquorice root extract WW can successfully be treated and reused for crop irrigation.

A comprehensive review on metal based active sites and their interaction with O3 during heterogeneous catalytic ozonation process: Types, regulation and authentication.

Heterogeneous catalytic ozonation (HCO) was a promising water purification technology. Designing novel metal-based catalysts and exploring their structural-activity relationship continued to be a hot topic in HCO. Herein, we reviewed the recent development of metal-based catalysts (including monometallic and polymetallic catalysts) in HCO. Regulation of metal based active sites (surface hydroxyl groups, Lewis acid sites, metal redox cycle and surface defect) and their key roles in activating O3 were explored. Advantage and disadvantage of conventional characterization techniques on monitoring metal active sites were claimed. In situ electrochemical characterization and DFT simulation were recommended as supplement to reveal the metal active species. Though the ambiguous interfacial behaviors of O3 at these active sites, the existence of interfacial electron migration was beyond doubt. The reported metal-based catalysts mainly served as electron donator for O3, which resulted in the accumulation of oxidized metal and reduced their activity. Design of polymetallic catalysts could accelerate the interfacial electron migration, but they still faced with the dilemma of sluggish Me(n+m)+/Men+ redox cycle. Alternative strategies like coupling active metal species with mesoporous silicon materials, regulating surface hydrophobic/hydrophilic properties, polaring surface electron distribution, coupling HCO process with photocatalysis and H2O2 were proposed for future research.

Effect of extrusion-spheronization granulation and manganese loading on catalytic ozonation of petrochemical wastewater.

The petrochemical secondary effluent (PSE) is typical refractory wastewater derived from the petrochemical industries, which requires advanced treatment due to the strict environmental protection policies. Catalytic ozonation is one of the most widely used advanced oxidation technologies in wastewater treatment because of its high mineralization rate, in which the alumina-based catalyst usually plays an important role. Extrusion-spheronization is a promising technique for the preparation of alumina spheres because the synthesized alumina particles have high sphericity, high specific surface aera and narrow particle size distribution. In this paper, two kinds of alumina-based catalysts (catalyst A: manganese nitrate added after alumina granulation and catalyst B: manganese nitrate added into alumina powder before granulation) were prepared by the extrusion-spheronization method and used for PSE treatment by catalytic ozonation. The prepared alumina samples were characterized by Brunauer-Emmett-Teller (BET) method, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning electron microscopy (SEM), while the wastewater samples were analyzed for Total organic carbon (TOC), UV254 and fluorescence spectroscopy. Results showed that manganese was uniformly distributed in both catalysts, and the specific surface area of two catalysts was 318.36 m2/g and 354.95 m2/g, respectively. Catalytic ozonation experiments were repeated nine times with each catalyst under the same conditions. The TOC removal rates for catalysts A and B in the first run were 48.88% and 49.06%, respectively, then it dropped to 28.05% for catalyst A but remained 47.81% for catalyst B after using for nine times. This implied that the long-term performance of catalyst B would be more stable than catalyst A. Similar result were found in three-dimensional fluorescence analysis. UV254 results indicated that the removal efficiency of aromatic and unsaturated substances by catalyst B was higher than catalyst A. A possible explanation is that the active component manganese oxide formed a catalyst skeleton in catalyst B, which makes it hard to dissolve. Effect of extrusion-spheronization granulation and manganese loading on advanced oxidant treatment of petrochemical wastewater.

Climate changes modulated the history of Arctic iodine during the Last Glacial Cycle.

Iodine has a significant impact on promoting the formation of new ultrafine aerosol particles and accelerating tropospheric ozone loss, thereby affecting radiative forcing and climate. Therefore, understanding the long-term natural evolution of iodine, and its coupling with climate variability, is key to adequately assess its effect on climate on centennial to millennial timescales. Here, using two Greenland ice cores (NEEM and RECAP), we report the Arctic iodine variability during the last 127,000 years. We find the highest and lowest iodine levels recorded during interglacial and glacial periods, respectively, modulated by ocean bioproductivity and sea ice dynamics. Our sub-decadal resolution measurements reveal that high frequency iodine emission variability occurred in pace with Dansgaard/Oeschger events, highlighting the rapid Arctic ocean-ice-atmosphere iodine exchange response to abrupt climate changes. Finally, we discuss if iodine levels during past warmer-than-present climate phases can serve as analogues of future scenarios under an expected ice-free Arctic Ocean. We argue that the combination of natural biogenic ocean iodine release (boosted by ongoing Arctic warming and sea ice retreat) and anthropogenic ozone-induced iodine emissions may lead to a near future scenario with the highest iodine levels of the last 127,000 years.

Plant age at the time of ozone exposure affects flowering patterns, biotic interactions and reproduction of wild mustard.

Exposure of plants to environmental stressors can modify their metabolism, interactions with other organisms and reproductive success. Tropospheric ozone is a source of plant stress. We investigated how an acute exposure to ozone at different times of plant development affects reproductive performance, as well as the flowering patterns and the interactions with pollinators and herbivores, of wild mustard plants. The number of open flowers was higher on plants exposed to ozone at earlier ages than on the respective controls, while plants exposed at later ages showed a tendency for decreased number of open flowers. The changes in the number of flowers provided a good explanation for the ozone-induced effects on reproductive performance and on pollinator visitation. Ozone exposure at earlier ages also led to either earlier or extended flowering periods. Moreover, ozone tended to increase herbivore abundance, with responses depending on herbivore taxa and the plant age at the time of ozone exposure. These results suggest that the effects of ozone exposure depend on the developmental stage of the plant, affecting the flowering patterns in different directions, with consequences for pollination and reproduction of annual crops and wild species.

The Influence of Environmental Conditions on Secondary Metabolites in Medicinal Plants: A Literature Review.

Medicinal plants, a source of different phytochemical compounds, are now subjected to a variety of environmental stresses during their growth and development. Different ecologically limiting factors including temperature, carbon dioxide, lighting, ozone, soil water, soil salinity and soil fertility has significant impact on medicinal plants' physiological and biochemical responses, as well as the secondary metabolic process. Secondary metabolites (SMs) are useful for assessing the quality of therapeutic ingredients and nowadays, these are used as important natural derived drugs such as immune suppressant, antibiotics, anti-diabetic, and anti-cancer. Plants have the ability to synthesize a variety of secondary metabolites to cope with the negative effects of stress. Here, we focus on how individual environmental variables influence the accumulation of plant secondary metabolites. A total of 48 articles were found to be relevant to the review topic during our systematic review. The review showed the influence of different environmental variables on SMs production and accumulation is complex suggesting the relationship are not only species-specific but also related to increases and decline in SMs by up to 50 %. Therefore, this review improves our understanding of plant SMs ability to adapt to key environmental factors. This can aid in the efficient and long-term optimization of cultivation techniques under ambient environmental conditions in order to maximize the quality and quantity of SMs in plants.

Oligomerization and Nitration of the Grass Pollen Allergen Phl p 5 by Ozone, Nitrogen Dioxide, and Peroxynitrite: Reaction Products, Kinetics, and Health Effects.

The allergenic and inflammatory potential of proteins can be enhanced by chemical modification upon exposure to atmospheric or physiological oxidants. The molecular mechanisms and kinetics of such modifications, however, have not yet been fully resolved. We investigated the oligomerization and nitration of the grass pollen allergen Phl p 5 by ozone (O3), nitrogen dioxide (NO2), and peroxynitrite (ONOO-). Within several hours of exposure to atmospherically relevant concentration levels of O3 and NO2, up to 50% of Phl p 5 were converted into protein oligomers, likely by formation of dityrosine cross-links. Assuming that tyrosine residues are the preferential site of nitration, up to 10% of the 12 tyrosine residues per protein monomer were nitrated. For the reaction with peroxynitrite, the largest oligomer mass fractions (up to 50%) were found for equimolar concentrations of peroxynitrite over tyrosine residues. With excess peroxynitrite, the nitration degrees increased up to 40% whereas the oligomer mass fractions decreased to 20%. Our results suggest that protein oligomerization and nitration are competing processes, which is consistent with a two-step mechanism involving a reactive oxygen intermediate (ROI), as observed for other proteins. The modified proteins can promote pro-inflammatory cellular signaling that may contribute to chronic inflammation and allergies in response to air pollution.

Potential Mitigation of Smoke Taint in Wines by Post-Harvest Ozone Treatment of Grapes.

When bushfires occur near grape growing regions, vineyards can be exposed to smoke, and depending on the timing and duration of grapevine smoke exposure, fruit can become tainted. Smoke-derived volatile compounds, including volatile phenols, can impart unpleasant smoky, ashy characters to wines made from smoke-affected grapes, leading to substantial revenue losses where wines are perceivably tainted. This study investigated the potential for post-harvest ozone treatment of smoke-affected grapes to mitigate the intensity of smoke taint in wine. Merlot grapevines were exposed to smoke at ~7 days post-veraison and at harvest grapes were treated with 1 or 3 ppm of gaseous ozone (for 24 or 12 h, respectively), prior to winemaking. The concentrations of smoke taint marker compounds (i.e., free and glycosylated volatile phenols) were measured in grapes and wines to determine to what extent ozonation could mitigate the effects of grapevine exposure to smoke. The 24 h 1 ppm ozone treatment not only gave significantly lower volatile phenol and volatile phenol glycoside concentrations but also diminished the sensory perception of smoke taint in wine. Post-harvest smoke and ozone treatment of grapes suggests that ozone works more effectively when smoke-derived volatile phenols are in their free (aglycone) form, rather than glycosylated forms. Nevertheless, the collective results demonstrate the efficacy of post-harvest ozone treatment as a strategy for mitigation of smoke taint in wine.

Discovery, Synthesis, and Optimization of Peptide-Based Antibiotics.

The rise of multidrug resistant bacteria has significantly compromised our supply of antibiotics and poses an alarming medical and economic threat to society. To combat this problem, it is imperative that new antibiotics and treatment modalities be developed, especially those toward which bacteria are less capable of developing resistance. Peptide natural products stand as promising candidates to meet this need as bacterial resistance is typically slow in response to their unique modes of action. They also have additional benefits including favorable modulation of host immune responses and often possess broad-spectrum activity against notoriously treatment resistant bacterial biofilms. Moreover, nature has provided a wealth of peptide-based natural products from a range of sources, including bacteria and fungi, which can be hijacked in order to combat more dangerous clinically relevant infections.This Account highlights recent advances in the total synthesis and development of a range of peptide-based natural product antibiotics and details the medicinal chemistry approaches used to optimize their activity.In the context of antibiotics with potential to treat Gram-positive bacterial infections, this Account covers the synthesis and optimization of the natural products daptomycin, glycocin F, and alamethicin. In particular, the reported synthesis of daptomycin highlights the utility of on-resin ozonolysis for accessing a key kynurenine residue from the canonical amino acid tryptophan. Furthermore, the investigation into glycocin F analogues uncovered a potent lead compound against Lactobacillus plantarum that bears a non-native thioacetal linkage to a N-acetyl-d-glucosamine (GlcNAc) sugar, which is otherwise O-linked in its native form.For mycobacterial infections, this Account covers the synthesis and optimization of teixobactin, callyaerin A, lassomycin, and trichoderin A. The synthesis of callyaerin A, in particular, highlighted the importance of a (Z)-2,3-diaminoacrylamide motif for antimicrobial activity against Mycobacterium tuberculosis, while the synthesis of trichoderin A highlighted the importance of (R)-stereoconfiguration in a key 2-amino-6-hydroxy-4-methyl-8-oxodecanoic acid (AHMOD) residue.Lastly, this Account covers lipopeptide antibiotics bearing activity toward Gram-negative bacterial infections, namely, battacin and paenipeptin C. In both cases, optimization of the N-terminal lipid tails led to the identification of analogues with potent activity toward Escherichia coli and Pseudomonas aeruginosa.

Effect of topical ozonated sunflower oil on second intention wound healing in turtles: a randomised experimental study.

BACKGROUND: Ozone is an antimicrobial agent that in experimental and case-control studies has been found to exert a positive effect on wound healing. Wild and pet chelonians frequently present insidious wounds exhibiting secondary infections and/or delayed healing. OBJECTIVES: Evaluate the effects of topical ozonated sunflower oil on second-intention healing of acute experimental skin wounds in red-eared sliders (Trachemys scripta elegans). METHODS: Randomised within-subject controlled study; Group 1 (n = 24) was used to assess clinical healing features; Group 2 (n = 12) was used for histological evaluation in which two sets of wounds were biopsied at 2, 7, 14, 21, 28 and 42 days over the course of the cicatrisation process. A single 6 mm diameter wound was made on each rear limb and topical ozonated (950 peroxide value) and non-ozonated sunflower oil were applied daily for one week on treated and contralateral control wounds, respectively. RESULTS: Mean wound size was significantly lower in the ozone-treated group at day 28 (p < 0.0001) with differences of clinical relevance (74.04% vs. 93.05% reduction of initial wound size). Histologically, the acute inflammatory reaction was enhanced in treated wounds, with significantly higher numbers of heterophils (p = 0.0016), lymphocytes (p < 0.001) and fibroblasts (p < 0.001). CONCLUSIONS: Daily topical application of ozonated sunflower oil over the course of one week improved the healing of acute, full-thickness skin wounds in chelonians. This clinical outcome was histologically correlated with an enhanced acute inflammatory reaction, as well as the production and remodelling of collagen fibres.

Evaluation of ozone technology as an alternative for degradation of free gossypol in cottonseed meal: a prospective study.

Free gossypol is a toxic compound which naturally occurs in cottonseed and its derivates, affecting animal and possibly human health. Consequently, alternatives for gossypol destruction must be evaluated. This work evaluated the emerging technology of ozone processing for free gossypol destruction in cottonseed meal. Ozonation was carried out in the actual cottonseed meal and also a model system, designed to describe the involved mode of action. The model system consisted of glass pearls beads covered with free gossypol. Ozonation was performed in two ways: as a static process, i.e., without homogenising the sample after placing them in the reactor, and also homogenising it. Ozone degraded free gossypol in all the systems, but reaching different levels. Free gossypol reduction was higher in the model system than the cottonseed meal, and higher in the homogenised processing than the static one: cottonseed meal in homogenised (56%) and static (25%); model system homogenised (98%) and static (80%). The obtained differences suggest a problem of gas penetration in the solid particles, the effect of unexposed surfaces due to contact areas, and the reaction with other organic molecules further than the target. Ozonation is a promising technique for gossypol degradation in cottonseed meal, but additional strategies are needed to optimise the ozonation process and evaluate toxicological aspects.

Method for the safe storage of sugar beets using an ion-ozone mixture.

BACKGROUND: Sugar refineries cannot modernize the current processing technology and increase their capacity in proportion to the increasing harvest of raw beets. This entails an increase in the processing time. Sugar beets are not subject to long-term storage, and when they are stored in inappropriate conditions, root crops rot, resulting in sugar loss. The aim of this study is to increase the safety of beets during long-term storage before processing and to develop a device for its implementation which will lead to an improvement in the biological value of sugar beet root crops and an increase in the efficiency of technological processes. METHODS: The experiment used sugar beets from the Koksu sugar plant and was carried out by treating sugar beets with an ion-ozone mixture to increase their shelf life. The treatment was carried out in an ion-ozone installation. Physicochemical and microbiological analyses were carried out using several methods: chemical extraction, potentiometry and photocolorimetry. RESULTS: The results of the study showed that when sugar beets were treated with ozone at a concentration of 0.5 g/m3 and 2 g/m3, the acidity decreased to 0.6 degrees, and the sugar content increased by 2.3% and 3.3%, respectively. When sugar beets were processed with an ozone concentration of 2 g/m3 and a molecular ion concentration of 1,000,000 units/cm3, a decrease in moisture was observed to 69%, the acidity decreased 2 times and the sugar content increased by 3%. When the beets were processed with an ozone concentration of 2 g/m3 and a molecular ion concentration of 1,000,000 units/cm3, a decrease in acidity was observed to 0.65-0.67 degrees, and the sugar content increased by 2-2.5%. Also, in all the above optimal processing conditions, a decrease in yeast growth was observed. CONCLUSIONS: As a result of the study, the following three optimal conditions were established for the processing of sugar beet root crops before storage: an ozone concentration of 0.5 g/m3 and 2 g/m3; an ozone concentration of 5 mg/m3 and molecular ions of 500,000 units/cm3; an ozone concentration of 2 g/m3 and molecular ions of 1,000,000 units/cm3.

Impact of aqueous ozone mixing on microbiological, quality and physicochemical characteristics of semi-dried buckwheat noodles.

The microbiological, microstructural, and physicochemical impact of aqueous ozone mixing (AOM) on semi-dried buckwheat noodles (SBWN) was elucidated in this study. Microbiological measurements declared that AOM reduced the initial total plate count (TPC) of SBWN significantly (P < 0.05) with a prolonged shelf-life of 2 ~ 5 days. Meanwhile, AOM reduced the cooking loss and water absorption along with the enhancement of hardness and tension force. Scanning electron microscopy (SEM) showed that the protein network of surface and cross section became continuous and compact, and wrapped starch granules more effectively. Moreover, an obvious increase in the intensity of the high molecular protein bands was observed in the sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) patterns. Furthermore, the sodium dodecyl sulfate extractable protein (SDSEP) under non-reducing condition obviously decreased, and then the SDSEP under reducing condition changed insignificantly (P > 0.05). These results indicated that AOM mainly promoted the protein cross-linking of SBWN by disulfide bond (SS) cross-links.

Effect of Surface Treatment by O3 and Chemical Activation by Alkali Metal on the Performance of ACFs on Adsorption and Desorption of BTX Gases.

In order to investigate the adsorption characteristics of activated carbon fibers (ACFs) with improved surface morphologies towards volatile organic compounds (VOCs), a commercial low-grade ACF was surface modified by successive surface treatment (ST) and chemical activation (CA) process. O3 was used as an ST agent for the formation of oxygen-containing functional groups on the carbon matrix of ACFs. CA was carried out after ST, using a KOH solution. After the successive ST-CA process, Brunauer-Emmett-Teller (BET) surface area and average pore diameter of ACFs were increased from 1483 m2/g to 2743 m2/g and enlarged from 1.931 nm to 2.512 nm, respectively. The successive ST-CA process also resulted in the adsorption capacities of benzene, toluene, and xylene of the ACFs to increase from 0.22 g-Ben./g-ACFs, 0.18 g-Tol./g-ACFs, and 0.19 g-Xyl/g-ACFs up to 0.37 g-Ben./g-ACFs, 0.35 g-Tol./g-ACFs, and 0.38 g-Xyl/g-ACFs, respectively.

Bioavailability of dissolved organic matter in biogas slurry enhanced by catalytic ozonation combined with membrane separation.

Large molecular weight pig biogas slurry (L-PBS) and small molecular weight pig biogas slurry (S-PBS) were separated from original pig biogas slurry (O-PBS) using a 100 kDa membrane. The original bioavailability and biosafety of L-PBS was very low. In order to enhance the total bioavailable dissolved organic nitrogen (TB-DON) and total bioavailable dissolved organic phosphorus (TB-DOP), optimum catalytic ozonation of L-PBS conditions were determined using Box-behnken design models (P < 0.0001) and intersection tests. The optimal values for ozone concentration, pH value, active catalyst concentration and reaction time were 2.63 mg·L-1, 6.48, 1.43 g·L-1 and 40 min, respectively. Catalytic ozonation can effectively decompose and transform 68.07% of L-PBS into S-PBS to improve content organic bioavailability, with a molecular weight distribution of 0-1 kDa (13.53%), 1-5 kDa (16.62%), 5-10 kDa (11.16%), 10-30 kDa (11.73%), 30-100 kDa (15.04%). Catalytic ozonation of L-PBS can reduce protein levels from 85.28% to 47.18%, but increases the proportion of fulvic and humic components from 10.22% to 32.67% and 4.51%-20.15%, respectively. Because catalytic ozonation changes the internal components and molecular weights of L-PBS, both saw increases in TB-DON and TB-DOP from 3.33% to 41.12% and 2.43%-37.88%, respectively, with a large number of TB-DON and TB-DOP derived from hydrophilic organic components during catalytic ozonation. These important internal mechanisms changed by catalytic ozonation can effectively reduce the ecotoxicity (IR, from 76.5% to 33.1%) and phytotoxicity (GI, enhanced from 35.4% to 70.3%) of L-PBS. Therefore, catalytic ozonation combined with membrane separation is a choice technology in improving the nutrition of biogas slurry and reduce its ecological risk.