[Pollution Characteristics of Organophosphorus Flame Retardants in a Wastewater Treatment Plant].

Sewage water, the influent of the secondary sedimentation tanks, the final effluent, sludge from biological pools, and dewatered excess sludge samples from eight wastewater treatment plants (WWPTs) in Suzhou, including those from seven A2/O processes and one oxidation ditch process, were collected in 2017 to study the pollution characteristics of organophosphorus flame retardants (OPFRs) in WWPTs. Accelerated solvent extraction (ASE) combined with a solid-phase extraction method was used to detect the concentration of 10 organic phosphorus flame retardant (OPFRs). The removal efficiency of OPFRs was compared and final daily emissions were estimated. The results showed seven kinds of OPFRs were detected in the influent, final effluent, and sludge. The total content of OPFRs in the influent ranged from 0.74 to 222.65 µg ·L-1 (average 65.56 µg ·L-1), while the content in the final effluent was between 0.46 and 175.41 µg ·L-1 (average 22.99 µg ·L-1). The concentration in the effluent of the secondary sedimentation tank was between 0.48 and 178.14 µg ·L-1 (average 43.14 µg ·L-1). The daily emission of OPFRs in final effluent was 36.69-2177.12 g ·d-1. The content in the dewatered excess sludge was between 89.32 and 596.24 µg ·g-1 dw (average 249.35 µg ·g-1 dw), the minimum daily emission was 3.57-7.15 kg ·d-1, and the maximum was 47.70-95.40 kg ·d-1. The oxidation ditch process has a good removal rate of OPFRs, at 92%, while the A2/O process removal rate covered a large range from 11%-99%. Three chlorinated OPFRs, TCEP, TCPP, and TDCPP, were the main components in the influent and final effluent, mainly because of the large consumption of OPFRs and also because the removal rate by the traditional wastewater treatment technology was low.

A novel naphthalene carboxylic acid-based ionic liquid mixed disperser combined with ultrasonic-enhanced in-situ metathesis reaction for preconcentration of triclosan and methyltriclosan in milk and eggs.

A microextraction method was developed based on utilization of a novel ionic liquid (IL) [C4MIM][NCA] as disperser and conventional ILs as extractor (IL-IL-DLLME). This method was integrated with an in-situ metathesis reaction to achieve high extraction efficiency by eliminating the loss of analytes in the discarded disperser after microextraction. Ultrasonic energy was compared to traditional mechanical shaking to accelerate the in-situ metathesis reaction. A 3-min ultrasonic treatment provided similar extraction efficiency as a 120-min mechanical shaking. Due to their strong acidity and lower solubility than traditional hydrophilic ILs, utilization of [C4MIM][NCA] in the IL-IL-DLLME procedure increased extraction recoveries (ERs) for triclosan (TCS) and methyltriclosan (MTCS) by 10-12% and also avoided an extra pH adjustment step. A series of operational parameters were optimized using single-factor screening and central composite design as follows: 65 µL extraction solvent, 150 µL [C4MIM][BF4] and [C4MIM][NCA] (132/18, v/v, µL) as dispersive solvent, 0.16 g NH4PF6 and 3.3 min ultrasonic time. Under optimized conditions with a fortification of 100 µg kg-1, ERs were 92.6-93.4% for TCS and 92.7-94.2% for MTCS in bovine milk and chicken egg samples. LODs for TCS and MTCS were 0.16-0.24 µg kg-1 and the enrichment factors were 21.8-23.1. Inter- and intra-day precisions had relative standard deviations of 3.3-5.4% for the optimized method. Overall, this newly developed IL-IL-DLLME method was effective for detecting trace levels of TCS and MTCS in real-world, animal-based foods. Prominent advantages of the new method include high precision and accuracy, high extraction efficiency, simple analytical operations, and no use of organic solvents making the procedure environmentally benign.