Deriving Ag_3PO_4–CaO composite as a stable and solar light photocatalyst for efficient ammonia degradation from wastewater

A novel Ag3PO4-CaO composite photocatalyst with enhanced photocatalytic activity was synthesized and utilized for degradation of ammonia from aqueous solution under sunlight. Ag3PO4 was prepared by pre- cipitation method, and the composite of AgjPO4-CaO was prepared via impregnation method. Utilization of eggshell for CaO synthesis provided a cost-effective and environmental friendly way for the hetero- geneous catalyst production. The as-prepared photocatalysts were characterized by FT-IR, FE-SEM, TEM, EDX, UV-vis and PL Results show that the Ag3PO4-CaO samples have excellent photocatalytic perfor- mances in the wide visible-light region. The effect of operating parameters like the content of Ag3PO4 in composite, initial ammonia concentration, pH of solution, catalyst dosage and oxygen supply was investi- gated. The photoeatalyst with 60 wt% content of Ag3PO4 had a high photocatalytic performance, because a low content of Ag3PO4 causes weak light absorption, and the excess amount of it results in serious electron-hole recombination due to the aggregation of AgjPO4 particles. The maximum ammonia degra- dation （about 70%） was achieved in 340 mg/L of ammonia, pH 11, and 1.25 g/L of catalyst in the presence of pure oxygen. In comparison to Ag3PO4, 60 wt% AgjPO4-CaO had a good stability and it could have been easily separated from the solution for recycling.

Aging Behaviors of Silicone Rubber Composite Materials under Outdoor Environment

We investigated the aging effect on the chemical structure of silicone rubber composite materials under outdoor environment. The variations of low molecular weight siloxanes in silicone rubber were probed by gas chromatography-mass spectrometry during the degradation process. The experimental results indicate that a series of cyclic siloxanes exist in both the virgin and aged silicone rubber samples, while the additional low molecular weight siloxanes（hexamethyl cyclotrisiloxane） only appear in the aged samples. Meanwhile, the total amounts of low molecular weight siloxanes in the aged samples are much less than those in the virgin ones. The loss of low molecular weight siloxanes is induced by the chain scission and depolymerization.

Ultrasonic-assisted synthesis of plasmonic Z-scheme Ag/AgCl/WO_3-nanoflakes photocatalyst in geothermal water with enhanced visible-light photocatalytic performance

In this study, the Ag/Ag Cl/WO3 plasmonic Z-scheme photocatalysts with different contents of Ag/Ag Cl nanoparticles（NPs） were prepared through a facile ultrasonic precipitation method in geothermal water,wherein the geothermal water served as the chlorine source. Then the photocatalytic activity was investigated by degradation of 4-Aminobenzoic acid（4-ABA） under visible-light irradiation. It was found that the as-prepared 50 wt% Ag/Ag Cl/WO3 photocatalyst showed the highest photocatalytic efficiency with 25.12 and 3.53 times higher than those of pure WO3 and Ag/Ag Cl, respectively. The active species trapping experiments indicated that h＋and ·O2-were key factors in 4-ABA photodegradation process. The possible plasmonic Z-scheme photocatalytic mechanism of photocatalytic reaction for 4-ABA degradation was proposed based on systematical characterizations. We hope this paper could give new ideas for further exploiting geothermal energy to design and fabricate highly efficient visible-light-driven photocatalysts for environmental remediation.

MnFe2O4@PANI@Ag Heterogeneous Nanocatalyst for Degradation of Industrial Aqueous Organic Pollutants

This paper reports a stable heterogeneous nanoparticles catalyst MnFe2O4@PANI@Ag for the degradation of azo dyes. In this synthesizing method, MnFe204 is used as magnetic core and polyaniline （PANI） a linker to stabilize the Ag nanoparticles （NPs） on the surface of catalyst. The method has a high ability to prevent Ag NPs from aggregation on the PANI surface, thus resulting in small size and highly dispersed Ag NPs. The composition and nano-structural features of polycrystalline sample were studied by X-ray powder diffractometry, Fourier transform infrared spectroscopy, and scanning electron microsco- py. Vibrating sample magnetometer measurements proved the super-paramagnetic property of the catalyst, and UV results demonstrated that MnFe2O4@PANI@Ag has a high ability to reduce the azo dyes, which come from industrial wastes in the form of pollutant. The nanocomposites could be readily separated by magnet and reused for the next four reductions with high generation efficiency.

Comparison effects of lanthanum stearate and antioxidants in epoxidized natural rubber

This work studied possibilities of using lanthanum stearate（LaS t） as an antioxidant in epoxidized natural rubber containing 25 mol.% expoxidation（ENR25） compounds. For comparison purposes, two commercial antioxidant 4010 NA and MB were also used. The influence of LaS t, antioxidant 4010 NA and MB on cure characteristics, mechanical properties, crosslink density, hot air aging and thermo-oxidative degradation were studied. The results indicated that the incorporation of LaS t and antioxidants could accelerate the vulcanization of ENR. The ENR vulcanizates with antioxidant MB had better mechanical properties than 4010 NA and LaS t. Compared with antioxidant 4010 NA and MB, the ENR25 vulcanizates with the addition of LaS t exhibited the best hot air aging resistance and thermo-oxidative stability.