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In response to antibiotic residues in the water, a novel advanced oxidation technology based on MgO2 was used to remediate sulfamethazine (SMTZ) pollution in aquatic environments. Upon appropriate regulation, the remarkable removal efficiency of SMTZ was observed in a UV/MgO2 system, and the pseudo-first-order reaction constant reached 0.4074 min−1. In addition, the better performance of the UV/MgO2 system in a weak acid environment was discovered. During the removal of SMTZ, the pathways of SMTZ degradation were deduced, including nitration, ring opening, and group loss. In the mineralization exploration, the further removal of residual products of SMTZ by the UV/MgO2 system was visually demonstrated. The qualitative and quantitative researches as well as the roles of reactive species were valuated, which revealed the important role of ·O2−. Common co-existing substances in actual wastewater such as NO3− HA, Cl−, Fe2+, Co2+, and Mn2+ can slightly inhibit the degradation of SMTZ in the UV/MgO2 system. Finally, the capacity of efficient degradation of SMTZ in actual wastewater by the UV/MgO2 system was proved. The results indicated that the innovative UV/MgO2 system was of great practical application prospect in antibiotic residue wastewater remediation. [ABSTRACT FROM AUTHOR]

(6) Species transport equation: HT ht Graph (6)where I c i is the tracer concentration, mol/L; HT ht is the effective diffusion coefficient, I D i SB I eff i sb is the effective viscosity coefficient, HT ht and is the turbulent Schmidt number. Keywords: fluid retention zone; heat exchanger; helical flow; RTD EN fluid retention zone heat exchanger helical flow RTD 681 696 16 07/21/22 20220701 NES 220701 1 Introduction The shell and tube heat exchanger (STHX) is dominant in the heat exchanger equipments. [Extracted from the article]

A series of novel phosphate orange-red phosphor, Sr9In(PO4)7:xSm3+ (0.01 < x < 0.30), were successfully synthesized from high-temperature solid-state synthesis in this work. Their crystal structure has been analyzed by the Rietveld refinement, which shows Sr9In(PO4)7 consists of a monoclinic cell (C2/c), which also confirms the successful doping, preferential site occupancy and local ligand environment of Sm3+. Luminescence properties of the samples have been systematically investigated including excitation and emission spectra, quantum efficiency, concentration quenching, fluorescence decay and temperature-dependent luminescence properties. Photoluminescence spectra exhibited typical peaks, corresponding to 4G5/2 → 6HJ transitions of Sm3+ ions, where J = 5/2, 7/2, 9/2, and 11/2, respectively. Moreover, the concentration quenching result revealed that the optimal doping content of Sm3+ was 0.15 mol, and based on the Dexter theory, the energy transfer between Sm3+ ions was found in dipole-dipole interactions. The quantum yield of Sr9In(PO4)7:0.15Sm3+ phosphor was acceptable (58.5%). Most importantly, the emission intensity of Sr9In(PO4)7:0.15Sm3+ remains constant (>97%) below 150 °C and the configurational coordinate diagram analysis demonstrated excellent thermal stability of the Sr9In(PO4)7:Sm3+ phosphor, which is superior to that of the previously reported and commercially available phosphors. These results suggest that the Sr9In(PO4)7:Sm3+ phosphor is a promising orange-red phosphor materials for white light emitting diodes. [ABSTRACT FROM AUTHOR]

Enabling the optimal usage of solar energy is considered to be one of the most pressing challenges in the photocatalytic remediation of water resident contaminants. Herein, a single-atom dispersed Ag loaded ultrathin g-C3N4 hybrid (AgTCM/UCN) was prepared through a facile co-polymerization of dicyandiamide with silver tricyanomethanide (AgTCM) and NH4Cl, and used as a visible light driven photocatalyst for the degradation of sulfamethazine (SMT) in the presence of peroxymonosulfate (PMS). Under UV light, visible light and simulated sunlight irradiation, the AgTCM/UCN/PMS process showed higher efficiency for SMT degradation than AgTCM/UCN, UCN/PMS, and g-C3N4/PMS systems. This enhanced photocatalytic activity may be attributed to the synergistic effects encompassing the surface plasmon resonance (SPR) of Ag, high surface area of UCN, and efficient charge separation of PMS. Electron–spin resonance (ESR) and reactive species (RSs) scavenger-quenching experiments revealed that SO4Ṗ− was generated following the addition of PMS, whereas O2Ṗ− and h+ were predominantly responsible for the degradation of SMT. Three degradation pathways of SMT were deduced, including the cleavage of sulfonamide bonds, SO2 extrusion, and the oxidation of the aniline moiety, based on mass spectrometry and theoretical calculations. The degradation of SMT in ambient water revealed that the AgTCM/UCN/PMS photocatalytic process can be efficaciously applied for the remediation of SMT contaminated natural waters, particularly sea water. [ABSTRACT FROM AUTHOR]

The development of facile and efficient synthetic approaches of carbon quantum dots loaded with mesoporous g-C3N4 (mpg-C3N4/CQDs) is of critical urgency. Here, a facile strategy was developed to synthesize the mpg-C3N4/CQDs by using calcinations of the mixture of CQDs, cyanamide, and silica colloid. The obtained composite still retained a considerable total surface area, which could offer a larger population of adsorption sites; therefore enhance the capacity for the adsorption of fluoroquinolones antibiotics (FQs). Under visible light irradiation, mpg-C3N4/CQDs demonstrated a higher photocatalytic activity for FQs degradation than did bulk g-C3N4 or mpg-C3N4. This enhancement might have been ascribed to the high surface area of the mpg-C3N4, unique up-converted photoluminescence (PL) properties, and the efficient charge separation of the CQDs. The eradication of FQs followed the Langmuir–Hinshelwood (L–H) kinetic degradation model and absorption pseudo-second-order kinetic model, indicating that surface reactions and chemical sorption played significant roles during the photocatalysis process. The results of electron spin resonance (ESR) technology and reactive species (RSs) scavenging experiments revealed that the superoxide anion radical (O2Ṗ−) and photo-hole (h+) were the primarily active species that initiated the degradation of FQs. Based on the identification of intermediates and the prediction of reactive sites, the degradation pathways of ofloxacin (OFX) were proposed. A residual antibiotic activity experiment revealed that mpg-C3N4/CQDs provided very desirable performance for the reduction of antibiotic activity. [ABSTRACT FROM AUTHOR]