Wan Su,Yufeng Zhang,Wenjuan Zhang,Shuting Xie,Xiaobo Sun,Jianqiang Meng
In this study, a nanofiltration (NF) polyamide hollow fiber thin film composite membrane with a low rejection and a high flux was prepared in consideration of the “trade-off” relation between salt rejection and permeate flux of the membrane. The membrane was able to retain the beneficial minerals in tap water while keeping the body healthy. The membrane prepared had a thinner active skin layer (<100 nm) than those of commercial membranes. A permeability of 30.07 L/m 2 /h and a rejection rate of 79.68% for 1,000 mg/L MgSO 4 at 0.2 MPa were obtained. In addiiton, Fe 3+ , Cu 2+ , and Pb 2+ were used to evaluate the heavy metal removal performance of the NF membrane. It was found that as the concentration of heavy metal ions increased to three times of the Standards for Drinking Water Quality (SDWQ) (GB5749-2006), and the rejections to all heavy metal ions were more than 76%. In addition, the NF membrane had a good long-term rejection stability for the heavy metal ions over a 12-month dynamic filtration experiment. The results showed that the newly prepared NF membrane has a good application prospect for domestic water purification.
In this work, a zeolitic imidazolate framework-based graphene oxide composite (ZIF-8@GO) was prepared and used as the adsorbent in hollow fiber stir bar sorptive extraction. The stir bar was constructed of a small section of hollow fiber filled with 5 mg ZIF-8@GO and a thin stainless wire of 1.5 cm long in its lumen, and used to extract the trace levels of phthalate esters from children’s food samples prior to gas chromatography–mass spectrometric detection. The ZIF-8@GO showed a high adsorption efficiency for the compounds containing aromatic rings. The main experimental parameters that can impact the extraction efficiency including extraction temperature, extraction time, stirring rate, sample salinity, and desorption conditions were investigated. Under the optimized conditions, the limits of detection (LODs) for the five phthalate esters (diethyl phthalate, dipropyl phthalate, diisobutyl phthalate, butylbenzyl phthalate, and di(2-ethylhexyl) phthalate) were 0.15–0.6 µg L −1 for CiCi beverage and pear juice samples, and 0.75–2.2 µg kg −1 for jam samples. The limits of quantitation (LOQs) were 0.5–2.0 µg L −1 for CiCi beverage and pear juice samples, and 2.5–7.5 µg kg −1 for jam samples. Wide linear ranges of 0.5–500.0 µg L −1 and 2.5–2000 µg kg −1 were obtained for CiCi beverage, pear juice samples and jam samples, respectively, with good repeatability (RSD < 11%) and high method recoveries (72%–100%). The lifetime test results showed that the ZIF-8@GO-based hollow fiber stir bar can be reused for 120 extraction cycles without a significant loss of extraction efficiency, indicating its high durability and stability. The established method was applied successfully for the determination of the phthalate esters (PAEs) in children’s food samples. Graphical abstract
危险品化学品经营许可证（带存储）