scholarly journals Transport of chromium(III) from mixtures of chromium ions by CTA- and PVC-based inclusion membranes

2018 ◽  
Vol 78 (8) ◽  
pp. 1792-1801
Author(s):  
J. Rajewski
Keyword(s):  
Phosphoric Acid ◽  
Ion Transport ◽  
Carrier Concentration ◽  
Vinyl Chloride ◽  
Polymer Matrix ◽  
Cellulose Triacetate ◽  
Process Time ◽  
Optimum Range ◽  
Poly Vinyl Chloride ◽  
The Stability

Abstract The author analysed the stability of cellulose triacetate (CTA)- and poly(vinyl chloride) (PVC)-based polymer inclusion membranes (PIMs) containing bis(2-ethylhexyl) phosphoric acid (D2EHPA) as a carrier for chromium(III) separation from mixtures of Cr(III)/Cr(VI) ions. He also studied the influence of carrier (D2EHPA) concentration in PVC- and CTA-based PIMs on chromium(III) ion transport, at different initial concentrations of the Cr(III) ions. Based on the results, the optimum range of carrier concentration in both membranes guaranteeing the fastest process was found. Moreover, PIMs with D2EHPA as the carrier worked as selective barriers for Cr(VI) ions. However, in the case of CTA/PIM, the increase in Cr(VI) concentration above 0.005 mol/dm3 negatively influenced Cr(III) transport, which was caused by the degradation of the polymer matrix. The PVC/PIM was not influenced by the Cr(VI) ions, thus PVC was definitely a better polymer for the synthesis of PIM for the separation of Cr(III/VI) ions. It was also demonstrated that both membranes were not stable over a long process time. The results reported in this study suggest that the factor that determines the stability of PIMs with D2EHPA is the presence of water in the membrane and the formation of unstable micellar structures.

scholarly journals Rust Conversion Performance of Phosphoric Acid-Gallic Acid in Vinyl Chloride Acrylic Emulsion

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 152
Author(s):  
Xin Wang ◽  
Qingjun Zhu ◽  
Xiangju Liu ◽  
Baorong Hou
Keyword(s):  
Phosphoric Acid ◽  
Gallic Acid ◽  
Vinyl Chloride ◽  
Salt Spray ◽  
Corrosion Current ◽  
Oxidation Reactions ◽  
Acrylic Emulsion ◽  
Conversion Performance ◽  
The Stability ◽  
Iron Complexation

This work studied the application of phosphoric acid-gallic acid in vinyl chloride acrylic emulsion and its rust conversion performance. The increase of phosphoric acid affected the stability of the system, leading to the rapid precipitation of flocculent precipitation. Rust conversion coating (RCC) showed the best synergistic conversion effect when gallic acid (GA) was 0.2 wt.% and phosphoric acid (PA) was 2 wt.%. XRD and FTIR analysis show that the components of adherent rust (AR) are α-FeOOH, γ-FeOOH and Fe3O4. The conversion products are ferric phosphate (FP) and ferric gallate (FG). The RCC can effectively treat the rusted steel (RS) produced by simulated marine atmospheric corrosion. The corrosion current density was reduced by three orders of magnitude, the adhesion reached 2.75 MPa, and the salt spray corrosion resistance was 20 days. The results of Raman, XPS, SEM and EDS show that the ionic dissolution of iron, complexation and further oxidation reactions occur at the interface between the adherent rust and the RCC. After rust conversion treatment, unreacted rust (UR) affects the further improvement of adhesion strength and anti-corrosion performance.

Zinc Hydroxystannate-Coated Mineral Grade Mg(OH)2 as Flame-Retardant and Smoke Suppression for Flexible PVC

2013 ◽  
Vol 652-654 ◽  
pp. 481-484 ◽  
Author(s):  
Chun Zheng Wang ◽  
Wei Hong Wu ◽  
Xia Ye ◽  
Lei Liu
Keyword(s):  
Flame Retardant ◽  
Vinyl Chloride ◽  
Smoke Suppression ◽  
Crosslinking Reaction ◽  
X Ray Diffraction ◽  
Limiting Oxygen Index ◽  
Smoke Suppressant ◽  
Poly Vinyl Chloride ◽  
Zinc Hydroxystannate ◽  
The Stability

A zinc hydroxystannate-coated mineral grade Mg(OH)2 (ZHSCMH) was synthesized as flame retardant and smoke suppressant for flexible poly (vinyl chloride). The powder of ZHSCMH was characterized by the x-ray diffraction (XRD) and scanning electron microscopy (SEM). The flame retardancy, smoke suppression and thermal behavior of PVC treated with ZHSCMH and mineral grade Mg(OH)2 were comparative studied by means of limiting oxygen index (LOI), smoke density rating (SDR), thermogravimetry (TG), differential thermogravimetry (DTG) and SEM. The results show that, ZHSCMH can be used as a high effective flame retardant and smoke suppressant for PVC. The flame retardant of ZHSCMH can effectively promote the crosslinking reaction of poly (vinyl chloride) (PVC) in the first stage, and improve the stability of the char residue in the second stage.

scholarly journals Synthesis of Polymer Inclusion Membranes based on Cellulose Triacetate for Recovery of Lanthanum(III) from Aqueous Solutions

2019 ◽  
Vol 19 (3) ◽  
pp. 288-292 ◽  
Author(s):  
Adam Makowka ◽  
Beata Pospiech
Keyword(s):  
Aqueous Solution ◽  
Phosphoric Acid ◽  
Aqueous Solutions ◽  
Metal Ions ◽  
Polymer Matrix ◽  
Tributyl Phosphate ◽  
Cellulose Triacetate ◽  
Nitrophenyl Octyl Ether ◽  
Source Phase ◽  
Ion Carrier

Abstract Polymer inclusion membrane (PIM) containing cellulose triacetate (CTA) as a polymer matrix and 2-nitrophenyl octyl ether (NPOE) as a plasticizer was developed. This membrane also contained di(2-ethylhexyl)phosphoric acid (D2EHPA) and tributyl phosphate (TBP) as the carriers of metal ions. The facilitated transport of lanthanum(III) from aqueous nitrate(V) solutions across PIM was studied. It was observed that metal ions were transported from the source phase into 2M H2SO4 as the receiving phase. The transport through PIM with D2EHPA as the ion carrier was found as the more effective method of lanthanum(III) removal from the aqueous solution than transport through PIM with TBP as the ion carrier.

scholarly journals The synergism of MgCO3 and 2ZnCO3·3ZnO·4H2O as flame retardants and smoke suppressants for flexible poly(vinyl chloride) (PVC)

e-Polymers ◽  
2011 ◽  
Vol 11 (1) ◽  
Author(s):  
Hongqiang Qu ◽  
Weihong Wu ◽  
Yunhong Jiao ◽  
Jixing Xie ◽  
Jianzhong Xu
Keyword(s):  
Vinyl Chloride ◽  
Flame Retardants ◽  
Decomposition Temperature ◽  
Char Residue ◽  
Initial Decomposition Temperature ◽  
Limiting Oxygen Index ◽  
Second Stage ◽  
Poly Vinyl Chloride ◽  
The Stability ◽  
Synergistic Agent

AbstractMgCO3 and 2ZnCO3·3ZnO·4H2O (AZC) as flame-retardants and smoke suppressants for flexible poly(vinyl chloride) (PVC) was evaluated using limiting oxygen index (LOI), smoke density rating (SDR) tests, scanning electron microscopy (SEM) and thermogravimetry analysis (TGA). The activation energy (Ea) of the original and flame retardant PVCs’ degradation processes was calculated by the Vyazovkin method. The results showed that the AZC can be used as a synergistic agent for MgCO3 as flame retardants agent of flexible PVC. The composites of MgCO3 and AZC cannot only decrease the initial decomposition temperature and increase the weight loss rate in the first stage, but also can promote the char formation in the second stage. The AZC decreased the Ea of the degradation reaction of PVC in the first stage and MgCO3 increased the Ea in the second stage, which means that the AZC combined with MgCO3, catalyzed the dehydrochlorination, promoted the early crosslinking for the PVC compound and improve the stability of the char residue. The SEM results also show that the char residue of MgCO3/AZC treated sample has a continuous and denser structure, which can be used as a barrier for the PVC bulk.

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