Long Pang

Occurrence, distribution, and potential affecting factors of organophosphate flame retardants in sewage sludge of wastewater treatment plants in Henan Province, Central China.

Organophosphate esters (OPEs) are widely used as flame retardants. In this study, the occurrence and distribution of six OPEs were investigated in sewage sludge from 24 wastewater treatment plants (WWTPs) in 18 cities of Henan province, Central China. The results indicated that all target OPEs were detected in the sludge samples with the detection rate of 95.8%, except tris(dichloropropyl)phosphate (TDCP). The total concentration of the six OPEs ranged from 38.6 to 508 μg kg(-1). Tris(2-chloroethyl)phosphate (TCEP), tris(2-butoxyethyl)phosphate (TBEP), and tris(2-chloroiso-propyl)phosphate (TCPP) were found to be predominant, with concentrations ranging from 2.50 to 203, 1.60 to 383, and 6.70-161 μg kg(-1), respectively. The potential factors affecting OPE levels in sewage sludge, such as wastewater source, sludge characteristics, operational conditions, treatment techniques, and total organic carbon (TOC) of sludge in WWTPs were investigated. The results indicated that the total concentration of OPEs in sewage sludge has no significant relationship with the individual parameters (p > 0.05). However, significant correlations were found between triphenyl phosphate (TPhP) level and treatment capacity (R = 0.484, p < 0.05), processing volume (R = 0.495, p < 0.05), and serving population (R = 0.591, p < 0.05). Furthermore, the relationship between treatment techniques and the total concentration of OPEs in sewage sludge was also investigated in this study, and the results illustrated that the levels of OPEs in sludge were independent of the solid retention time (SRT).

Trace determination of organophosphate esters in environmental water samples with an ionogel-based nanoconfined ionic liquid fiber coating for solid-phase microextraction with gas chromatography and flame photometric detection.

Organophosphate esters, widely used as flame retardants and plasticizers, are regarded as a class of emerging pollutants. In this work, a novel approach was developed for the fabrication of a solid-phase microextraction fiber by using hybrid silica-based materials with immobilized ionic liquids with sol-gel technology, and the prepared solid-phase microextraction fiber was then coupled with gas chromatography and flame photometric detection for the analysis of six organophosphate esters. The high loading of 1-hexadecyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide was confined within the hybrid network. The developed solid-phase microextraction fiber possesses a coating thickness of ∼35 μm with good thermal stability and long lifetime. The parameters affecting the extraction efficiency such as extraction time, temperature, pH, and ionic strength of the sample solution were optimized. Under the optimized conditions, the limits of detection were in the range of 0.04-0.95 μg L-1 , and the precision of the method assessed with repeatability and reproducibility of (RSD%) ˂13 and ˂29%, respectively. The proposed method was successfully applied to determine the six organophosphate esters in three real water samples, with recoveries in the range of 64.8-125.4% at two different spiking concentration levels. As a result, the proposed method demonstrated its potential for application in trace determination of organophosphate esters in actual water samples.

Application of Fe3O4@MIL-100 (Fe) core-shell magnetic microspheres for evaluating the sorption of organophosphate esters to dissolved organic matter (DOM)

Organophosphate esters (OPEs) are widely used as flame retardants and plasticizers in many products and materials. Because of the potential biologic toxicity on human beings, OPEs are regarded as a class of emerging pollutants. Dissolved organic matters (DOM) have significant effects on the bioavailability and toxicity of the pollutants in the environment. Negligible-depletion solid-phase microextraction (nd-SPME) is an efficient way for measuring the freely dissolved pollutants but suffers from long equilibrium time. Metal-organic frameworks (MOFs) are a class of porous crystalline materials with unique properties such as high pore volume, regular porosity, and tunable pore size, being widely used for the extraction of various organic compounds. Here we developed a novel method for quick determination the sorption coefficients of OPEs to DOM in aquatic phase using Fe3O4@MIL-100 (Fe) core-shell magnetic microspheres. The mesoporous structures of the as-synthesized microspheres hindered the extraction of OPEs which associated with humic acid due to the volume exclusion effect. However, the freely dissolved OPEs can access into the mesoporous and then were extracted by MIL-100 (Fe). Due to the small pore size (4.81 nm), large surface area (141 m2 g-1), high pore volume (0.17 g3 g-1), and ultra-thin MOFs layers, Fe3O4@MIL-100 (Fe) core-shell magnetic microspheres have large contact area for the analytes in aqueous phase and therefore the diffusion distance was largely shortened. Besides, the microspheres can be collected conveniently after the extraction process by applying a magnetic field. Compared to the nd-SPME method with 35 h equilibration time (t90%), the proposed method for these studied OPEs only need 24 min to achieve equilibration. The sorption coefficients (logKDOC) of the OPEs to humic acid were ranged from 3.84-5.28, which were highly consistent with the results by using polyacrylate-coated fiber and polydimethylsiloxane-coated fiber with nd-SPME.

Degradation of organophosphate esters in sewage sludge: Effects of aerobic/anaerobic treatments and bacterial community compositions

This dataset provides detail information on the analytical methods of organophosphate esters (OPEs) in sludge samples, including the sample preparation, ultra-high performance liquid chromatography-tandem mass spectrometric (UPLC-MS/MS) analysis, quality assurance and quality control (QA/QC). The concentration of target OPE compounds in collected samples of four individual treatment was provided, including aerobic composting combined with pig manure (T1), aerobic composting without pig manure (T2), anaerobic digestion combined with pig manure (T3), and anaerobic digestion without pig manure (T4). To investigate the variation of bacterial community compositions, principal components analysis (PCA) was provided based on the high-throughput sequencing. These data would be useful for clarifying the removal of OPEs under aerobic and anaerobic conditions. Besides, it also provides important information on the potential bacterial strains responsible for the biodegradation of OPEs in each treatment.

Polymeric ionic liquid based fused silica fiber by chemical binding for headspace solid-phase microextraction of organophosphate esters in water samples

ABSTRACT In this paper, a convenient method was developed for preparing polymeric ionic liquid based fiber coating onto a fused silica fiber by using covalent bonding for headspace solid-phase microextraction of five organophosphorus esters from real water samples. 1-vinyl-3-(3-triethoxysilylpropyl)-4,5-dihydroimidazolium chloride was anchored on the silica layer by covalent bonding and then the polymeric ionic liquid layer was formed via free radical copolymerization with vinyl-substituted imidazolium in the presence of azobisisobutyronitrile as initiator. The limits of detection ranged from 0.68 to 100 ng L−1. The intra- and inter-day precisions, evaluated by relative standard deviation, were in the range of 4–8% and 1–10%, respectively. The recoveries of spiked real water samples were in the range of 73–110% and 77–118%, respectively, at two different concentration levels.