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The obtained reaction coefficients were then used to validate the model under various operating conditions, namely concentration, relative humidity, irradiation, and velocity variations. Higher concentration and irradiation, as well as lower relative humidity and velocity, resulted in more by-products generation. It was also observed that with enhancing residence time, mineralization efficiency (or CO2 formation) and by-products generation increases through PCO reaction. The model validation provided acceptable accuracy for both steady-state and transient conditions. Finally, the Health Risk Index was used to investigate the implications of generated by-products on human health under varying operating conditions.The excess residues of fluoride ions cause serious human health problems, making their detection highly valuable. In this work, a whole-cell-based biosensor was presented for the detection of fluoride ions, which can inhibit the color reaction of 3,3',5,5',-tetramethylbenzidine (TMB) catalyzed by the CotA-laccase of spore surface. This reaction for the detection of fluoride ions could be read out through UV-vis spectrophotometer, smartphone, or standard colorimetric card within 10 min. Under optimum conditions, a linear range of 1-600 μmol L-1 with a detection limit of 0.12 μmol L-1 (3σ/k) was achieved for fluoride ions detection by using UV-vis spectrophotometer. The biosensor coupling with smartphone had a good linear response to fluoride ions concentration in the range of 5-600 μmol L-1 with LOD of 0.90 μmol L-1 (3σ/k). The standard colorimetric card can be directly used for recognizing the fluoride ions level via naked-eyes. A portable kit based on a colorimetric card and smartphone was developed and has been successfully applied for fluoride ions monitoring in surface waters and groundwater. This developed method has several advantages such as rapid, outstanding selectivity and anti-interference, low-cost, ease of operation and storage, and eco-friendliness, meeting the demands of point-of-care testing of fluoride ions and disease prevention.Sewage sludge-derived biochar (SBC) could remove organic contaminants in environment and reuse the sludge effectively. In this study, urea-doped SBC (NSBC) was prepared, characterized, and applied as heterogeneous catalytics to peroxydisulfate (PDS) activation. Sulfadiazine (SD), a widely used antibiotic, was used as a model pollutant to evaluate the efficiency and mechanism of this system. The degradation rate of SD increased to 100% after 4 h when 1 g/L of NSBC was added to the system with a SD concentration of 20 mg/L. In this study, it was confirmed that there were two important pathways in the degradation of SD by NSBC/PDS system the free radical on the surface of NSBC and the nonradical (1O2) in the solution. The doping of N atoms makes neighboring C atoms positively charged, thereby making the direct transfer of electrons with S2O82- and the generation of 1O2 via nonradical pathway easy. In addition, the CO functional group formed during the pyrolysis of NSBC can produce 1O2 in a similar way. A total of 22 SD degradation products were identified, and 4 possible pathways were proposed. This study provide supplement for the degradation mechanism of organic compounds by carbon-based materials.In order to challenge high working temperature, low response and low selectivity of present NO2 sensor, porous SnO2 nanotoasts with a large surface area (79.94 m2/g) were synthesized. Thick film sensors fabricated by the SnO2 nanotoasts exhibited a high response to NO2 gas operating at room temperature. Excellent performance for NO2 sensing gas at 50 °C, included the high response of 105.2 (10 ppm), low detection limitation of 0.1 ppm, fast response within 10 s, and wide range of 0.1-10 ppm (R2 = 0.9931). These sensors also demonstrated perfect selectivity, moisture resistance and 90 days of long-term stability. SnO2 nanotoasts sensor has excellent detection ability in actual detection. The superior response of porous SnO2 nanotoasts towards NO2 was attributed to the special porous structure with large specific surface area and oxygen vacancies in sensing material, which helped adsorption of the target gas molecules onto the sensing surfaces and transfer of the charge.During ozonation in wastewater treatment plants, ozone reacts with emerging pollutants, which are partially removed through the secondary treatment, as long as, with their biotransformation products, triggering the formation of ozonation transformation products (TPs). Although the transformation of parent compounds (PCs) and their metabolites has been reported in the literature, the probable transformation of biotransformation products has not been investigated so far. This study evaluates the fate of citalopram (CTR) and four of its biotransformation products (DESCTR, CTRAM, CTRAC and CTROXO) during ozonation experiments. A Gaussian curve-based trend analysis was performed for the first time for the automated detection of TPs in ozone concentrations ranging from 0.06 to 12 mg/L. In total 46 ozonation TPs were detected; 7 TPs of CTR, 10 of DESCTR, 9 of CTRAM, 12 of CTRAC and 8 of CTROXO and were structurally elucidated based on their high resolution tandem mass spectra interpretation and tandem mass spectra similarity with the respective PC. Results have demonstrated that the examined compounds follow common transformation pathways in reaction with ozone and that common TPs were formed through the ozonation of different structurally-alike compounds. Moreover, the toxicity of the identified TPs was predicted with an in-house risk assessment program.Hematite (α-Fe2O3) has been commonly used as an eco-friendly catalyst for peroxymonosulfate (PMS) to generate free radicals (SO4•- and/or •OH). However, the activation efficiency of PMS relies heavily on the conversion of Fe(III) to Fe(II) that is slow and rate-limiting. In this study, oxygen vacancies enriched α-Fe2O3 was prepared from thermally treated goethite (α-FeOOH) and employed as a PMS activator. Systematic characterization demonstrated that α-Fe2O3 with most abundant oxygen vacancies could be obtained by heating α-FeOOH at 300 °C. The as-prepared α-Fe2O3 exhibited excellent catalytic activity in activation of PMS for oxidation of sulfamethoxazole (SMX, k = 0.04 min-1). The SMX degradation rate was found to be positively correlated with the concentration of oxygen vacancies. https://www.selleckchem.com/products/disodium-r-2-hydroxyglutarate.html Quenching experiments, EPR, LC/MS and XPS analysis revealed that singlet oxygen (1O2) was the predominant reactive oxygen species. The effects of pH, PMS dosage, catalyst loading, temperature, and anions on SMX degradation were comprehensively investigated.

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