Groundwater solutes influence the adsorption of short-chain perfluoroalkyl acids (PFAA) to colloidal activated carbon and impact performance for in situ groundwater remediation.

Subsurface injection of colloidal activated carbon (CAC) is an in situ remediation strategy for perfluoroalkyl acids (PFAA), but the influence of groundwater solutes on longevity is uncertain, particularly for short-chain PFAA. We quantify the impact of inorganic anions, dissolved organic matter (DOM), and stabilizing polymer on PFAA adsorption to a commercial CAC. Surface characterization supported PFAA chain-length dependent adsorption results and mechanisms are provided.

Anoxic degradation of chlorpyrifos by zerovalent monometallic and bimetallic particles in solution.

The degradation of highly toxic and persistent chlorinated organic compounds by zerovalent metals (ZVMs) has received considerable attention for in situ groundwater remediation. Due to its abundance and low toxicity, iron has been mostly applied for such purposes, despite several limitations, such as rapid surface passivation and little efficacy towards certain contaminants. Given that, we evaluated monometallic zerovalent iron (ZVI), copper (ZVC) and zinc (ZVZ), and bimetallic copper-coated ZVI (ZVI/Cu) and ZVZ (ZVZ/Cu) for anoxic reductive degradation of chlorpyrifos (CP).

Amicarbazone degradation promoted by ZVI-activated persulfate: study of relevant variables for practical application.

Alarming amounts of organic pollutants are being detected in waterbodies due to their ineffective removal by conventional treatment techniques, which warn of the urgent need of developing new technologies for their remediation. In this context, advanced oxidation processes (AOPs), especially those based on Fenton reactions, have proved to be suitable alternatives, due to their efficacy of removing persistent organic compounds. However, the use of ferrous iron in these processes has several operational constraints; to avoid this, an alternative iron source was here investigated: zero-valent-iron (ZVI).

Evaluation of sulfathiazole degradation by persulfate in Milli-Q water and in effluent of a sewage treatment plant.

The presence of antibiotics and their metabolites in natural waters has raised some concern among scientists around the world because it can lead to bacterial resistance and other unknown consequences to mankind and wildlife. Persulfate (PS)-driven oxidation is a new technology that has been used successfully to remediate contaminated sites, but its use to treat wastewater, especially sewage treatment plant (STP) effluent, is still scarce. This paper describes the effect of several persulfate activation methods for degrading sulfathiazole (STZ) in Milli-Q water and in STP effluent.

Zero valent iron mediated degradation of the pharmaceutical diazepam.

Parameters that influence the zero valent iron mediated degradation of the pharmaceutical diazepam (DZP) were evaluated including the iron concentration and its pre-treatment, the effect of complexation with EDTA and oxic versus anoxic condition. It was observed that acid pre-treatment of iron particles is important for degradation efficiency and that H(2)SO(4) is a better choice than HCl, resulting in higher degradation of DZP. Under oxic conditions, the degradation of DZP achieved 96% after 60 min using Fe(0) (25 g L(-1)) pre-treated with H(2)SO(4) in the presence of EDTA (119 mg L(-1)), while mineralization achieved around 60% after the same time.

1,3-diene probes for detection of triplet carbonyls in biological systems.

Electronically excited triplet carbonyls are formed during the oxidative degradation of polyunsaturated fatty acids, amino acids, and beta-dicarbonyl metabolites. Due to their long lifetime and high alkoxyl radical-like reactivity, triplet carbonyls may initiate deleterious reactions in biological systems. Here we study the quenching properties of conjugated dienes, specifically 2,4-hexadienoate (sorbate) and its alkyl ester, on triplet acetone generated chemically (thermolysis of tetramethyl-1,2-dioxetane) or enzymatically (horseradish peroxidase-catalyzed aerobic oxidation of isobutanal).