In this study, we fabricated a porous calcium alginate/graphene oxide composite aerogel by using polystyrene colloidal particles as sacrificial template and graphene oxide as a reinforcing filler. Owing to the excellent metal chelation ability of calcium alginate and controlled nanosized pore structure, the as-prepared calcium alginate/graphene oxide composite aerogel (mp-CA/GO) can reach the adsorption equilibrium in 40 min, and the maximum adsorption capacity for Pb2+, Cu2+ and Cd2+ is 368.2, 98.1 and 183.6 mg/g, respectively. This is higher than most of the reported heavy metal ion sorbents. Moreover, the mp-CA/GO can be regenerated through simple acid-washing and be used repeatedly with little loss in performance. The adsorption mechanism analysis indicates that the mp-CA/GO adsorb the heavy metal ions mainly through the ion exchange and chemical coordination effects.
Intumescent flame retardant (IFR) has received the considerable attention ascribed to the inherent advantages including non-halogen, low toxicity, low smoke release and environmentally friendly. In this work, a novel charring agent poly (piperazine phenylaminophosphamide) named as PPTA was successfully synthesized and characterized by Fourier transform infrared spectra (FTIR) and X-ray photoelectron spectroscopy (XPS). Then, a series of flame-retardant EP samples were prepared by blending with ammonium polyphosphate (APP) and PPTA. Combustion tests include oxygen Index (LOI), verticalBurning Test (UL-94) and cone calorimeter testing,these test results showed that PPTA greatly enhances the flame retardancy of EP/APP. According to detailed results, EP containing 10 wt% APP had a LOI value of 30.2%,but had no enhancement on UL-94 rating.However, after both 7.5 wt% APP and 2.5 wt% PPTA were added, EP-7 passed UL-94 V-0 rating with a LOI value of 33.0%. Moreover, the peak heat release rate (PHRR) and peak of smoke product rate (PSPR) of EP-7 were greatly decreased. Meanwhile, the flameretardant mechanism of EP-7 was investigated by scanning electron microscopy (SEM), thermogravimetric analysis/infrared spectrometry (TG-IR) and X-ray photoelectron spectroscopy (XPS). The corresponding results presented PPTA significantly increased the density of char layer, resulting in the good flame retardancy.
K E Y W O R D Sepoxy resin, flame retardancy, mechanism, thermal behavior
Due to its novel properties and unique utility, nitriles are attractive as an additive to lithium-ion battery electrolytes. However, when it is applied to high-voltage batteries, the effects and mechanisms are not clearly explained. In particular, we need to explore its mechanism. In this work, adiponitrile (ADN) has been employed as the additive in the electrolyte 1 M LiPF 6 -EC/DMC/EMC (1:1:1 by weight). The cycling tests for LiNi 0.5 Mn 1.5 O 4 half-cells after 150 cycles at 1 C (1 C = 147 mA/g) from 3.5 to 5.0 V show that adding 1 wt % ADN into the electrolyte can improve the capacity retention of the battery from 69.9% to 84.4%. Moreover, the rate performance can also be significantly improved. Based on the EIS measurement, a little ADN can stabilize the interfacial impedance avoiding a possible increase during cycling. To further clarify its mechanism, XRD, SEM, XPS measurements, and DFT calculations have been conducted, which display that when adding it into the liquid electrolyte, the cathode particles maintain good spinel shape and the molecule groups of ADN-S tend to be oxidized primarily to form a very thin film on the cathode surface. All these results indicate that ADN has potential applications in high performance electrolytes for storage systems.
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