The formation of hydroxylated intermediates is the first step in the persulfate-based advanced oxidation processes (AOPs) and depends directly on the oxidation degree of recalcitrant pollutants. Therefore, the monitoring of hydroxylated intermediates plays a vital role in persulfate-based AOPs for evaluating the oxidation degree and understanding the degradation mechanism. In this work, based on the attractive amplification of luminol chemiluminescence (CL) signals by hydroxylated intermediates, we developed a rapid, sensitive, and simple CL-based method to monitor hydroxylated intermediate (i.e., 3,5-diethyl-1,4-benzenediol) generated in persulfate-based AOPs of 1,2-divinylbenzene (DVB). The possible mechanism of the proposed CL system was that hydroxylated intermediates could be oxidized by persulfate in alkaline solution to form superoxide anion radicals and thus lead to an increase in the luminol CL. Finally, the proposed CL system was successfully applied in monitoring hydroxylated intermediates generated during persulfate-based AOPs under different degradation conditions, whose validity and reliability were verified by liquid chromatography–mass spectrometry (LC-MS) and Fourier-transform infrared spectroscopy (FT-IR). The generality of the proposed CL system was verified by monitoring hydroxylated intermediates generated in persulfate-based AOPs of methylbenzene and benzoic acid. These results suggested that this present CL system provided a promising indicator for monitoring hydroxylated intermediates in persulfate-based AOPs.
Hao-hao Ren,Peng-cheng Li,Ya-nan Wu,Jin-bo Hu,Gang Zhang,Yong-gang Yan
A series of semi-aromatic copoly(ether ether amide)s (hydroquinone (HQ) (0%)-HQ (100%)) were synthesized by 1,1-bis(4-hydroxyphenyl)-1-phenylethane (BHPPE), 1,4-benzenediol (HQ) and 1,6- N , N ′-bis(4-fuorobenzamide) hexane (BFBH) in this work. The inherent viscosities of copoly(ether ether amide)s were in the range of 0.487–0.769 dl g −1 . Following with increase of the content of HQ, the resultant polymers were converted from amorphous to crystalline. The copolymers were found to have high glass transition temperatures ( T g ) of 141.4–155.6°C and weight-loss temperature ( T 5% ) of 423.3–434.3°C. They can be hot-pressed into films with tensile strength of 63.3–87.6 MPa, and storage modulus over 0.8 GPa at about 150°C, indicating good thermal and mechanical property of the obtained copolymers. The results of rheological property showed that the copolymers had good melt flowability and thermal stability. Additionally, the introduction of HQ improved the corrosion resistance of copolymers, the obtained polymers HQ (60%), HQ (80%) and HQ (100%) exhibited better corrosion resistance than that of HQ (0%). Especially, HQ (80%) and HQ (100%) were insoluble in organic polar solvents such as DMSO, DMF because of their crystalline nature, indicating that they had potential to be applied to the corrosion-resistant materials.