Synthesis of novel modified acrylamide copolymers for montmorillonite flocculants in water-based drilling fluid.

A study was conducted to treat the water-based drilling fluid through coagulation-flocculation. Innovative modified acrylamide copolymers were utilized as montmorillonite flocculants to improve drilling performance and reduce environmental contamination. A series of acrylamide copolymers was prepared by in situ free radical polymerization in aqueous medium using ammonium persulfate as a radical initiator. The chemical structure of the prepared copolymers was confirmed by FT-IR (Fourier-Transform Infrared Spectroscopy) and the polydispersity indices of the copolymers determined using gel permeation chromatography. Thermal gravimetric analysis showed that the copolymers have a very high temperature tolerance, i.e. they are stable up to 390 °C. In this paper, acrylamide copolymers were used as coagulant with cationic, anionic groups or both of them simultaneously. Consequently, in order to clarify the relationship between inhibitive properties, sedimentation volume measurement, SEM (scanning electron microscope), XRD (X-ray diffraction) and contact angle were adopted. Some factors including molecular weight and molecular chain affecting the interaction between copolymers and clay particles were analyzed. Anionic sample with the highest molecular weight can reduce the interlayer spacing of the hydrated clay to the minimum. Amphoteric sample exhibits the best performance as a coagulant in comparison with other copolymers.

Synthesis of water soluble ionic liquid copolymers based on acrylamide and investigation of their properties in flocculating of clay suspensions.

To overcome water absorption and swelling by clay mineral layers, it is very important to develop stabilizing additives for water-based drilling fluids, where organic polymers are used as raw materials. Acrylamide copolymers, acting as flocculating agents, have the potential to separate minerals such as montmorillonite. In this study, three water-soluble copolymers containing acrylamide-amphoter, acrylamide-amphoter-anion, and acrylamide-amphoter-cation were synthesized and characterized using various analytical techniques, including Fourier-transform infrared spectroscopy, nuclear magnetic resonance, gel permeation chromatography, differential scanning calorimetry, thermogravimetric analysis, and derivative thermal gravimetric techniques. These copolymers were employed as flocculants to treat water suspensions containing montmorillonite particles, and a range of analytical methods, such as sedimentation volume measurement, scanning electron microscopy analysis, X-ray diffraction analysis, and contact angle measurement, were employed to identify the relationship between inhibitive performance. The flocculation of montmorillonite plates was attributed to the electrostatic attractions between montmorillonite and the synthesized copolymers. High molecular weight copolymers offer greater thermal stability and better flocculation characteristics for water-based drilling fluids. Among the tested copolymers, the acrylamide-amphoter-anion sample, with the highest molecular weight, exhibited the best performance as a coagulant when compared to the other copolymers.

Magnetic solid phase extraction based on poly(ß-cyclodextrin-ester) functionalized silica-coated magnetic nanoparticles (NPs) for simultaneous extraction of the malachite green and crystal violet from aqueous samples.

In this research, an efficient sorbent based on poly(ß-cyclodextrin-ester)-functionalized silica-coated magnetic nanoparticles (MNPs-CDP) was prepared and used for magnetic solid-phase extraction of the malachite green (MG) and crystal violet (CV) from water samples prior to their determination by high-performance liquid chromatography-ultra violet detection (HPLC-UV). The synthesized nanoparticles were characterized by the field emission-scanning electron microscopy (FE-SEM) and Fourier transform infrared spectroscopy (FT-IR). Of course, the factors, which could influence the extraction efficiency like pH, sorbent amount, salt content, extraction time, desorption time, eluent type, and volume and sample volume, were optimized by response surface methodology. Then, for both of MG and CV, good linearity (0.1-200 µg L-1, r2 ≥ 0.99) was achieved under the optimized conditions. The limits of detection (LODs) and the limits of quantification (LOQs), for both of MG and CV, were 0.03 µg L-1 and 0.1 µg L-1, respectively. Precision of the method expressed as the relative standard deviations (RSDs) at concentration level of 100 µg L-1 was 5.6 and 4.2 for MG and CV, respectively. Ultimately, usability of proposed method was investigated by analysis of CV and MG in tap water, fish pond water, and the lake water, and the satisfactory recoveries were obtained in the range of 92-100.5%.

Optimization of effective parameters in the synthesis of nanopore anodic aluminum oxide membrane and arsenic removal by prepared magnetic iron oxide nanoparicles in anodic aluminum oxide membrane via ultrasonic-hydrothermal method.

In this study, a new anodized aluminum oxide (AAO) nanostructure membrane was synthesized by anodization process under a constant voltage, in oxalic acid solution that was improved with trace amounts of sulfuric acid at room temperature. The effect of various parameters on the morphology of the synthesized nanostructures such as voltage, electrolyte composition, anodization time and type of stripping solution were investigated. According to the results, corrosion of the walls, size regularity, diameter and number of the pores increased in the presence of sulfuric acid (0.018 mol.L-1). Nitrogen adsorption-desorption analysis confirmed significant porosity, array and uniformity of the pore size in the synthesized nanoporous membrane. A new modification method was used based on ultrasonic-hydrothermal method to modify the synthesized AAO with Fe3O4/SiO2 nanoparticles for metals and metalloids removal from aqueous solution. In this method, Fe3O4/SiO2 nanoparticles were placed very regularly and uniformly on the surface and inside the pores. This modification was confirmed by characterization techniques. The modified AAO@Fe3O4/SiO2 membrane showed excellent results for removing arsenic from aqueous media.

2-Naphthalenthiol derivatization followed by dispersive liquid-liquid microextraction as an efficient and sensitive method for determination of acrylamide in bread and biscuit samples using high-performance liquid chromatography.

In this research, an ultrasonic-assisted extraction followed by 2-naphthalenthiol derivatization and dispersive liquid-liquid microextraction of acrylamide (AA) was developed as simple and sensitive sample preparation method for AA in bread and biscuit samples using high performance liquid chromatography. Influence of derivatization and microextraction parameters were evaluated and optimized. Results showed that the derivatization of AA leads to improve its hydrophobicity and chromatographic behavior. Under optimum conditions of derivatization and microextraction, the method yielded a linear calibration curve ranging from 10 to 1000 µg L-1 with a determination coefficient (R2) of 0.9987. Limit of detection (LOD) and limit of quantification (LOQ) were 3.0 and 9.0 µg L-1, respectively. Intra-day (n = 6) and inter-day (n = 3) precisions based on relative standard deviation percent (RSD%) for extraction and determination of AA at 50 and 500 µg L-1 levels were less than 9.0%. Finally, the performance of proposed method was investigated for determination of AA in some bread and biscuit samples, and satisfactory results were obtained (relative recovery ≥ 90%).

Simple and fast preparation of graphene oxide@ melamine terephthaldehyde and its PVC nanocomposite via ultrasonic irradiation: Chemical and thermal resistance study.

Melamine terephthaldehyde modified graphene oxide (MTR-GO) with optimum content was easily prepared via ultrasonication method and used as anti-corrosion additive for Poly (vinyl chloride) (PVC). The effects of ultrasonicated MTR-GO on the mechanical, chemical and thermal resistance of the PVC were thoroughly studied. Change percentage of tensile strength and weight change percentage of PVC (P) and PVC/MTR-GO nanocomposite (PN) in acetone and sodium hypochlorite (NaClO) media at two different exposure temperature (20 °C and 50 °C) were examined. The PN sample showed lower change loss percentage of tensile strength in acetone uptake as compared with P sample at 20 °C. In higher temperature (50 °C), P sample was decomposed while PN still showed tensile data. The change loss percentage in tensile strength of PN sample showed 13% change at 50 °C in sodium hypochlorite while P sample showed 63% change for the parameter. Protective behavior of MTR-GO nanofiller on PVC matrix against thermal HCl releasing was investigated by Congo red tests. The results showed that the nanocomposite release less amount of HCl as compare to the neat PVC.

Designed biocompatible nano-inhibitor based on poly(ß-cyclodextrin-ester) for reduction of the DEHP migration from plasticized PVC.

The easy migration of di(2-ethylhexyl) phthalate (DEHP) from the plasticized PVC (P-PVC) poses a serious threat to human health and the ecosystems. Thus, its control migration from the P-PVC products is very important. In this work, a poly(ß-cyclodextrin-ester) network (ß-CDP) was synthesized via reaction of ß-cyclodextrin with 3,3',4,4'-benzophenone tetracarboxylic dianhydride. As a potential inhibitor for reduction of the DEHP migration, the ß-CDP was grafted to Fe3O4 nanoparticles. Poly(ß-cyclodextrin-ester) functionalized Fe3O4 nanoparticles (MNP-CDP) has been used in PVC/DEHP system as a reactive nano-inhibitor to reduce DEHP migration. Thermal stability and mechanical properties of obtained films were investigated. DEHP migration tests of the P-PVC films were also carried out by using Gas chromatography. It was found that by incorporating the small amounts of nano-inhibitor in PVC/DEHP system, the migration of DEHP effectively reduced from the P-PVC samples about 65% without any serious changes in mechanical and thermal properties of the P-PVC films.