Fenton-like membrane reactor assembled by electron polarization and defect engineering modifying Co3O4 spinel for flow-through removal of organic contaminants.

The application of Fenton-like membrane reactors for water purification offers a promising solution to overcome technical challenges associated with catalyst recovery, reaction efficiency, and mass transfer typically encountered in heterogeneous batch reaction modes. This study presents a dual-modification strategy encompassing electron polarization and defect engineering to synthesize Al-doped and oxygen vacancies (OV)-enriched Co3O4 spinel catalysts (ACO-OV). This modification empowered ACO-OV with exceptional performance in activating peroxymonosulfate (PMS) for the removal of organic contaminants. Moreover, the ACO-OV@polyethersulfone (PES) membrane/PMS system achieved organic contaminant removal through filtration (with a reaction kinetic constant of 0.085 ms-1), demonstrating outstanding resistance to environmental interference and high operational stability. Mechanistic investigations revealed that the exceptional catalytic performance of this Fenton-like membrane reactor stemmed from the enrichment of reactants, exposure of reactive sites, and enhanced mass transfer within the confined space, leading to a higher availability of reactive species. Theoretical calculations were conducted to validate the beneficial intrinsic effects of electron polarization, defect engineering, and the confined space within the membrane reactor on PMS activation and organic contaminant removal. Notably, the ACO-OV@PES membrane/PMS system not only mineralized the targeted organic contaminants but also effectively mitigated their potential environmental risks. Overall, this work underscores the significant potential of the dual-modification strategy in designing spinel catalysts and Fenton-like membrane reactors for efficient organic contaminant removal.

Simultaneously promoted reactive manganese species and hydroxyl radical generation by electro-permanganate with low additive ozone.

A novel water treatment process combining electrolysis, permanganate and ozone was tested in the laboratory. The combination showed synergistic effects in degrading various organic contaminants (like diclofenac, sulfamethoxazole, carbamazepine, etc.). A small amount of O3 (1 mg L-1, 60 mL min-1) significantly improved the oxidation and mineralization ability of an electro-permanganate process by generating more reactive manganese species and hydroxyl radicals. The combination required less energy consumption than comparable processes. Mechanism experiments showed that the ·OH involved was mainly generated by cathode reduction, homogeneous manganese catalysis, and heterogeneous manganese catalysis of O3 decomposition. Reactive Mn species were generated by electro-reduction, ·OH oxidation or/and O3 activation. In situ generated Mn (Ⅳ)s plays a vital role in generating ·OH and reactive Mn species. ·OH generated by O3 catalysis could transfer colloid Mn (Ⅳ)s to free Mn (Ⅴ)aq and Mn (Ⅵ) aq. And both the ·OH and RMnS played the dominant role for DCF removal. Increasing permanganate dosage, O3 concentration, the current density, Cl-, or humic acid, and decreasing the pH all enhanced the degradation of diclofenac, but the presence of PO43- or HCO3- inhibited it. Supplementing electrolysis with permanganate and O3 might be a practical, sustainable, and economical technology for treating refractory organics in natural waters.

Effective treatment of residue of acrylic acid production using a fluid-bed/fixed-bed system with low energy consumption.

In order to effectively deal with large amounts of complex organic pollutants in the harmful distillation residues with low energy consumption, a novel two-stage fluid-bed/fixed-bed system was designed to catalyze oxidation of acrylic acid production residue. The effects of fluid-bed temperature, gaseous hourly space velocity (GHSV), and oxygen excess rate on the purification of acrylic acid production residue in the two-stage fluid-bed/fixed-bed system were studied to prove the feasibility of the method. The chemical oxygen demand (COD) of the discharged liquid was <100 mg/L, and the volatile organic compounds (VOCs) of the discharged gas amounted to <10 mg/m3 with a fluid-bed temperature of 380°C, emulsified residue's GHSV of 0.28 L/(kgcat ·hr), and O2 excessive rate of more than 4.32. The result of techno-economics indicates the feasibility of the long-term operation of process. Results further illustrate the advantages of the proposed two-stage fluid-bed/fixed-bed system, which can treat acrylic acid production residue with high efficiency (COD < 100 mg/L, VOCs < 10 mg/m3 ) and low energy consumption (~24,856 kw·hr/ton) in the chemical industry. PRACTITIONER POINTS: A novel two-stage fluid-bed/fixed-bed system was developed for acrylic acid production residue treatment. No extra energy was required at low temperature in the two-stage fluid-bed/fixed-bed system. Purification of residue could be finished at low temperature by the catalytic pyrolysis and catalytic oxidation process. The two-stage system did not produce toxic gases and particulate matters.

[Analysis of Pb(II), Cd(II) and Cu(II) in Chinese medicine by the system of porphyrin complexes and sulfhydryl cotton fiber].

The reaction of alpha beta gamma delta-tetra(p-sulfophenyl)porphyrin (TPPS4) with Pb(II), Cd(II) or Cu(II) has been studied in this article, and the spectra of the Pb(II)-TPPS4, Cd(II)-TPPS4 and Cu(II)-TPPS4 show the spectral absorption of these complexes with high sensitivity. The molar absorptivities of Pb(II)-TPPS4, Cd(II)-TPPS4 and Cu(II)-TPPS4 are 2.5 x 10(5) L x mol(-1) x cm(-1), 5.2 x 10(5) L x mol(-1) x cm(-1) and 4.2 x 10(5) L x mol(-1) x cm(-1), respectively. With the sulfhydryl cotton fiber separation-enrichment method, this analytical system of porphyrin complexes has been successfully applied to determining the trace amounts of Pb(II), Cd(II) and Cu(II) in Ginkgo bilobal leaves and tea leaves. The RSD of determining 10(-6)-10(-7) g x g(-1) Pb(II), Cd(II) or Cu(II) in samples lies between 3.3%-9.6%, and the recovery of added standard lies between 90%-103%. The proposed analytical method has the advantage of high sensitivity, simplicity and high efficiency of interfere-resisting.