Selectivity and competition in the chemical oxidation processes for a binary pharmaceutical system in treated sewage effluent

Controlled electrocatalysis of the dechlorination and detoxification of chlorinated ethylenes to avoid production of highly toxic intermediates

In this study, electrochemical dechlorination and detoxification of a mixture of chlorinated ethylenes was investigated under various conditions using a double monoatomic synergistic metal catalytic cathode. Electrocatalytic degradation of mixed chlorinated with stepwise voltage and alternating current exhibited excellent dechlorination efficiency. The removal ratios of 1,2-dichloroethylene (1,2-DCE), trichloroethylene (TCE), and tetrachloroethylene (PCE) reached 78.79 %, 79.27 %, and 93.44 % in 10 min, and 98.14 %, 97.56 %, and 98.70 % in 30 min, respectively. The toxicity was evaluated using a quantitative structure-activity relationship model. The cumulative toxicity was reduced to 8.00 % of the initial cumulative toxicity in 30 min. An electrochemical dechlorination strategy for selective degradation and detoxification of mixtures of chlorinated pollutants is proposed. Controlled dechlorination and detoxification under low-voltage control avoided the accumulation of toxic intermediates. Cumulative toxicity was reduced by strategies of selective dechlorination, and segmented and alternating current decreased the energy consumption. The strategy provides a basis for alternating current electrocatalytic dechlorination associated with mixed chlorinated pollutants treatment.

Improvement of TNBC immune checkpoint blockade with a microwave-controlled ozone release nanosystem

Despite revolutionary achievements have been made in clinical cancer therapy, the immune checkpoint blockade regimen still presents limited efficacy on tumors lack of neoantigens exposure. Here, we designed and synthesized an on-demand microwave-controlled ozone release nanosystem to specifically generate reactive oxygen species in tumor mass. By taking advantage of iRGD modification, the synthesized nanosystem can be specifically enriched in the tumor microenvironment and subsequently internalized by tumor cells. Triggered by the low-power microwave, ozone was released from the nanocarriers and inhibited tumor cell growth in vitro and in vivo. Molecular mechanism investigation further unraveled that the released-ozone induced cytolytic cell death through the rapid generation of reactive oxygen species such as hydroxyl radical. The tumor-specific neoantigen derived from this immunogenic cell death promoted cytotoxic T-lymphocytes infiltration, which provided a fundament for immune checkpoint blockade therapy. In the triple-negative breast cancer animal model, tumor-specific delivery of ozone significantly improved the systematical anti-tumor efficacy of the PD-1 blockade antibody. Notably, tumor-locally confined microwave-controlled release avoided systematic toxicity in the tested animals. Collectively, our nanosystem provides a novel controllable strategy for promoting immune checkpoint blockade therapy, especially in tumor types deficient in infiltrated T-lymphocytes.

Mechanism and Kinetic Analysis of the Degradation of Atrazine by O3/H2O2

In phosphate buffer, the degradation of ATZ by ozone/(O3/H2O2) under various circumstance was explored and the degradation mechanism and dynamics were probed. The findings revealed that when maintaining the reaction temperature at 25 °C, the H2O2 concentration and the O3 concentration were 20 mol/L and 20 mol/L, respectively. Moreover, the degradation rate of 5 mol/L ATZ under the influence of O3/H2O2 was 92.59% in phosphate buffer at pH7. The mechanism analysis showed that HO• and O3 underwent co-oxidized degradation and that the HO• and O3 oxidation degradation ratios were close to 1:1 under acidic conditions. Furthermore, HO• oxidative degradation dominated the ATZ degradation process. The kinetics analysis showed that the ATZ kinetics of O3/H2O2 degradation were more compatible with quasi-second-order reaction kinetics under different temperatures, pH values, and H2O2 concentrations.

Adsorbent Minimization for Removal of Ibuprofen from Water in a Two-Stage Batch Process

Pharmaceutical products in water, also known as personal pharmaceutical products or PCPPs, are developing contaminants that have the potential to impair human health and the environment in a variety of ecosystems. In this work, waste date stones, a waste product obtained from the seedless dates manufacturing industry, were used to make acid-activated carbon. This material has been utilized to extract the medicinal component ibuprofen from water, with a high adsorption capacity of 126 mg ibuprofen per g of waste date stone-generated activated carbon. A design study was conducted to minimize the amount of activated carbon required, utilizing a two-stage batch adsorption system to optimize the usage of the activated carbon. To test the model and compare the quantities of adsorbent required in the two-stage and single-stage systems under various conditions, several variables were entered into the design model.

A critical review on ibuprofen removal from synthetic waters, natural waters, and real wastewaters by advanced oxidation processes

Ibuprofen (IBP) is one ubiquitous drug prescribed as anti-inflammatory, analgesic, and antipyretic. It has been detected in effluents of wastewater plant treatments, sewage sludge, hospital wastewaters, surface waters, and drinking water due to its continuous release to the environment, mainly from the excretion in the urine of animals and humans. IBP is a carcinogenic and non-steroidal endocrine disrupting drug with harmful effects over fungal, bacterial, algae, microorganisms, crustacean, and fish species, and can be potentially hazard for human health. Since conventional treatments remove inefficiently this drug, many advanced oxidation processes (AOPs) have been developed aiming their abatement from waters to avoid their harmful health problems. This paper presents an exhaustive and critical review on the application of AOPs to treat synthetic waters, natural waters, and real wastewaters polluted with IBP alone or mixed with other common drugs covering up to 2020. The characteristics and main results obtained for single, hybrid, and sequential treatments are described. Dielectric barrier or pulsed-corona discharges are detailed among the single processes. Hybrid processes such as photocatalysis (UV/H₂O₂, UV/chlorine, TiO₂/UV), hybrid ozonation (O₃/H₂O₂, electro-peroxone, catalytic ozonation), Fenton-based processes (photo-Fenton, electro-Fenton, photoelectro-Fenton), zero-valent iron, ultrasonic, peroxymonosulfate, and persulfate, are discussed. The effect of the kind of irradiation (UV, visible, solar) on photo-assisted processes is analyzed. Sequential processes with biological pre- or post-treatments using or not membranes for natural water and real wastewater remediation are described. Finally, 38 by-products detected during IBP removal by AOPs are reported, allowing envisaging three parallel pathways for its initial degradation.

Superior selectivity of high-frequency ultrasound toward chorine containing-pharmaceuticals elimination in urine: A comparative study with other oxidation processes through the elucidation of the degradation pathways

This work considered the sonochemical degradation (using a bath-type reactor, at 375 kHz and 106.3 W L^-1, 250 mL of sample) of three representative halogenated pharmaceuticals (cloxacillin, diclofenac, and losartan) in urine matrices. The action route of the process was initially established. Then, the selectivity of the sonochemical system, to degrade the target pharmaceuticals in simulated fresh urine was compared with electrochemical oxidation (using a BDD anode, at 1.88 mA cm^-2), and UVC/H₂O₂ (at 60 W of light and 500 mol L^-1 of H₂O₂). Also, the treatment of cloxacillin in an actual urine sample by ultrasound and UVC/H₂O₂ was evaluated. More than 90% of the target compounds concentration, in the simulated matrix, was removed after 60 min of sonication. However, the sono-treatment of cloxacillin in the real sample was less efficient than in the synthetic urine. The ultrasonic process achieved 43% of degradation after 90 min of treatment in the actual matrix. In the sonochemical system, hydroxyl radicals in the interfacial zone were the main degrading agents. Meanwhile, in the electrochemical process, electrogenerated HOCl was responsible for the elimination of pharmaceuticals. In turn, in UVC/H₂O₂ both direct photolysis and hydroxyl radicals degraded the target pollutants. Interestingly, the degradation by ultrasound of the pharmaceuticals in synthetic fresh urine was very close to the observed in distilled water. Indeed, the sonodegradation had a higher selectivity than the other two processes. Despite the sono-treatment of cloxacillin was affected by the actual matrix components, this contrasts with the UVC/H₂O₂, which was completely inhibited in the real urine. The sonochemical process led to 100% of antimicrobial activity (AA) elimination after 75 min sonication in the synthetic urine, and ∼ 20% of AA was diminished after 90 min of treatment in the real matrix. The AA decreasing was linked to the transformations of the penicillin nucleus on cloxacillin, the region most prone to electrophilic attacks by radicals according to a density theory functional analysis. Finally, predictions of biological activity confirmed that the sono-treatment decreased the activity associated with cloxacillin, diclofenac, and losartan, highlighting the positive environmental impact of degradation of chlorinated pharmaceuticals in urine.

Enhanced catalytic ozonation of ibuprofen using a 3D structured catalyst with MnO2 nanosheets on carbon microfibers

Heterogeneous catalytic ozonation is an effective approach to degrade refractory organic pollutants in water. However, ozonation catalysts with combined merits of high activity, good reusability and low cost for practical industrial applications are still rare. This study aims to develop an efficient, stable and economic ozonation catalyst for the degradation of Ibuprofen, a pharmaceutical compound frequently detected as a refractory pollutant in treated wastewaters. The novel three-dimensional network-structured catalyst, comprising of δ-MnO₂ nanosheets grown on woven carbon microfibers (MnO₂ nanosheets/carbon microfiber), was synthesized via a facile hydrothermal approach. Catalytic ozonation performance of Ibuprofen removal in water using the new catalyst proves a significant enhancement, where Ibuprofen removal efficiency of close to 90% was achieved with a catalyst loading of 1% (w/v). In contrast, conventional ozonation was only able to achieve 65% removal efficiency under the same operating condition. The enhanced performance with the new catalyst could be attributed to its significantly increased available surface active sites and improved mass transfer of reaction media, as a result of the special surface and structure properties of this new three-dimensional network-structured catalyst. Moreover, the new catalyst displays excellent stability and reusability for ibuprofen degradation over successive reaction cycles. The facile synthesis method and low-cost materials render the new catalyst high potential for industrial scaling up. With the combined advantages of high efficiency, high stability, and low cost, this study sheds new light for industrial applications of ozonation catalysts.