Enhanced removal of dimethyl phthalate using heterogeneous UVC/VUV-Fenton amendment with Fe3O4@CM-ß-CD/rGO catalyst: Efficiency, degradation mechanism and toxicity.

Dimethyl phthalate (DMP) is widely used as plasticizer, and this kind of plastic industry wastewater is refractory due to the complex chemical structure and endocrine disrupting property. In order to effectively degrade and mineralize DMP contaminated wastewater, a heterogeneous UVC/VUV-Fenton catalyst system was designed with the amendment of targeted design catalyst Fe3O4@CM-ß-CD/rGO with core-shell like structure covered with loose convex folded lamellar. The optimum removal and mineralization efficiency of DMP were 98.6 % and 62.8 % in 30 min with 150 mg L-1 Fe3O4@CM-ß-CD/rGO and 8 mmol L-1 H2O2. This efficient and fast removal were attributed to a variety of photocatalytic oxidative active species •OH, •O2- and h+ with 59.6%, 29.1% and 9.9% contribution ratio, which mainly took effect on benzene ring open and side-chain fracture by oxidative, hydrolysis and hydrogen substitution determined by the rupture energy requirement from chemical bond in DMP. The target function of CM-ß-CD in catalyst controlled the photo-electron generation rate and shorten mass transfer distance by the cladding lamellar, moreover, rGO accelerated the redox between Fe (II) and Fe (III) and electron transfer. The catalytic recovery and removal to DMP kept above 90 % after five recycles. This study provided an excellent performance catalyst and an effective photo-Fenton approach and for the treatment of endocrine disrupting wastewater.

Phytochelatin-Mediated Cultivar-Dependent Cd Accumulations of Lactuca sativa and Implication for Cd Pollution-Safe Cultivars Screening.

Cd pollution-safe cultivar (Cd-PSC) is a feasible strategy to minimize Cd contamination in leafy vegetables. The shoot Cd concentrations of 23 Lactuca sativa cultivars under Cd stress ranged from 0.124 to 2.155 mg·kg-1 with a maximum cultivar difference of 8 folds. Typical Cd-PSC C16 (L) and high-Cd-accumulating cultivar C13 (H) were screened to investigate the mechanisms of Cd accumulations in L. sativa through determining Cd concentrations, Cd subcellular distributions, phytochelatin profiles, and phytochelatin biosynthesis-related genes' expressions. Higher Cd distribution in a heat stable fraction in C13 (H) indicated that the high Cd accumulation trait of C13 (H) mainly depended on the Cd-phytochelatin complexes. Root phytochelatin concentrations were significantly elevated in C13 (H) (5.83 folds) than in C16 (L) (2.69 folds) (p < 0.05) under Cd stress. Significantly downregulated expressions of glutathione S-transferase rather than the regulation of phytochelatin synthesis genes in the root of C13 (H) might be responsible for sufficient glutathione supply for phytochelatins synthesis. These findings suggested that phytochelatin elevation in C13 (H) would favor the Cd root to shoot transportation, which provides new insights into the phytochelatin-related cultivar-dependent Cd accumulating characteristic in L. sativa.