Fourier Transform Infrared Test Research Articles

Effect and Mechanism of Zirconium Crosslinker on Retarding Degradation of HPAM/PEI Gel System in Medium-Salinity Reservoirs

Summary The objective of this paper is to investigate the effect of the addition of zirconium crosslinker on retarding the degradation of the partially hydrolyzed polyacrylamide/polyethyleneimine (HPAM/PEI) gel system. Dehydration and degradation under salinity conditions pose serious challenges to the effectiveness of the HPAM/PEI system used for water control treatment in heterogeneous reservoirs. In this study, rheological tests, Fourier transform infrared (FTIR) spectroscopy, and 13C nuclear magnetic resonance (NMR) spectroscopy are used to elucidate the characteristics and mechanisms of dehydration and degradation of HPAM/PEI gel in medium-salinity conditions. The effects of three types of zirconium crosslinkers on the gelation performance of the HPAM/PEI system are evaluated. Furthermore, the mechanism by which an organic zirconium complex (ZrOr complex) with triethanolamine (TEA) and lactic acid (LA) as ligands improves the stability of the HPAM/PEI system under medium-salinity conditions is revealed. The results indicate that ZrOr complex notably retards the degradation of the HPAM/PEI system under medium-salinity conditions (50 g/L) for more than 60 days while improving its gel strength. TEA and LA as ligands have a positive effect on crosslinking of HPAM with the organic Zr4+ complex by modulating the availability of Zr4+ and the homogeneity of the crosslinking reaction. Specifically, our data suggest that TEA stabilized Zr4+ and retarded its release through its chelating effect, while LA improved the efficiency and effectiveness of the crosslinking reaction by increasing the solubility of Zr4+ and providing additional carboxyl groups. The synergistic effect of the two ligands significantly improved the properties of the final crosslinked product. Evidence from FTIR, 13C NMR, and microstructural tests supports the conclusion that the retardation of degradation and enhancement of gelation performance in the HPAM/PEI system by ZrOr complex are associated with its crosslinking with carboxyl groups produced by HPAM hydrolysis, leading to the formation of a more uniform and compact network structure. A field trial conducted in the Beiyao Block demonstrated the potential of the ZrOr complex to extend the treatment lifetime of the HPAM/PEI gel system in medium-salinity reservoirs.

Effect of Acidulated Phosphate Fluoride Gel on Zirconia Intaglio Surface: An In-Vitro Study

Abstract Aim: To evaluate the micro-shear bond strength (µ-SBS) of resin-modified glass ionomer cement and to assess the chemical and topographical changes in the zirconia fitting surface induced by acidulated phosphate fluoride (APF) gel using scanning electron microscope (SEM) analysis and Fourier transform infrared (FTIR) spectroscopy. Materials and Methods: Thirty-two samples were prepared from two zirconia materials, UPCERA HT White and BruxZir® Solid Zirconia, milled by a computer-aided design/computer-aided manufacturing system. From each zirconia sample, six plates were prepared for FTIR and SEM testing. Following sintering, the samples were divided into control and test groups for each material. The APF gel (1.23%) was applied to the intaglio surface of each test group. To measure the µ-SBS between the zirconia materials and luting cement, 20 rectangular samples of zirconia material were prepared. Ten samples were obtained from Upcera and ten from Bruxzir, with five assigned to the control and five to APF groups. Statistical Analysis: For the µ-SBS test, independent samples t test was conducted to determine the level of significance between the tested groups. Results: FTIR spectroscopy revealed new bands for Upcera and Bruxzir zirconia owing to ion exchange between the formed sodium phosphate and the zirconia surface and the formation of zirconium phosphate by an ester reaction. SEM assessment identified lines, scratches, or surface dissociation that appeared on the intaglio–zirconia surface after conditioning. The µ-SBS test, as indicated by the independent samples t test, showed a significant increase in bond strength of 1.266 and 1.566 MPa for Upcera and Bruxzir zirconia, respectively. Conclusion: This study offers new practical, cost-effective, and accurate tests to enhance the µ-SBS of luting cement to yttria-stabilized tetragonal zirconia polycrystal ceramics.

Laboratory investigation on inhibition of polyvinyl alcohol used for wireline coring drilling

To address the problems of wall collapse, cuttings slurrying, and scaling on the inner wall of the drill pipe, which often occur in small-diameter diamond wireline core drilling, the inhibition properties of polyvinyl alcohol (PVA) was investigated, and the formulation of solids-free drilling fluid with PVA as the inhibitor were completed. PVA has the advantages of fast adsorption and easy regulation of rheological properties Firstly the inhibition effect of PVA was compared with that of common inorganic salts (sodium chloride, NaCl, potassium chloride, KCl) by bentonite dispersion test, linear swelling test, shale rolling recovery test and mud ball immersion test in this study. Then, the inhibition mechanism of PVA was analyzed with potentiometric particle size tests, Fourier transform infrared (FT-IR) and X-ray Diffraction (XRD) measurements. Based on the outstanding inhibition performance of PVA, tackifiers and filtration reducers were preferred through the compatibility test. And finally, the effects of various contaminants on the comprehensive performance of the formulated solids-free drilling fluids were evaluated. The results showed that PVA exhibited better inhibition of clay hydration and dispersion in shale recovery and linear swelling compared to NaCl and KCl, which was particularly evident in the mud ball immersion test. FT-IR and XRD tests revealed that the inorganic salts were used to replace the cations with larger radius and high degree of hydration in the clay layer by ion exchange ti achieve the effect of clay de-watering by reducing the spacing of the clay interlayer and the electrostatic repulsion between the particles. However, PVA is strongly adsorbed on the clay surface in the form of hydrogen bonds due to its unique multi-hydroxyl chain structure, forming a hydrophobic barrier to prevent water molecules from entering the clay layer, thus inhibiting the hydration and swelling of the clay. Using PVA as an inhibitor, compounded with xanthan gum, sulfonated lignite resin and sulfonated gilsonite (FT-1), the solids-free drilling fluid is promising for use in diamond wireline core drilling in complex formations.

The Effect of Silica Concentration on The Absorption Properties of Silica-Based Ceramic Membrane

Water pollution is currently an increasingly widespread environmental problem. Methylene blue is a synthetic dye used in the textile industry which pollutes the aquatic environment. The absorption of Methylene Blue textile dye which pollutes the environment uses silica precipitate as a filler in ceramic membranes with a clay matrix. Silica precipitate added to the ceramic membrane varies with a concentration of 0.3 %, 1.01 %, 1.68 %, 2.34 % and 2.99 %. The membrane will be characterized using Fourier Transform Infrared (FTIR) testing to determine the functional groups of the components it contains. Testing the absorption of methylene blue contaminant content from artificial wastewater using the UV-Vis Spectrophotometry test. The FTIR test carried out compared the functional groups of membrane samples before and after sintering. The results obtained from the FTIR test were that the membrane after sintering contained silica and some PEG, while the membrane before sintering contained other components such as PVA, PEG, water molecules and silica. The UV-Vis test carried out on the membrane gave results that the membrane was 0.3 %, 1.01 %, 1.68 %, 2.34 % and 2.99 % respectively has a removal efficiency of 58.0 %, 54.0 %, 59.3 %, 64.0 % and 66.4 %, where the best removal efficiency of methylene blue was on a membrane filled with 2.99 % of silica. Tests on the membrane showed that an increase in silica concentration was in line with an increase in the quality of the membrane’s performance in rejecting methylene blue contaminants.

In Vitro Characterizations of Poly(Ethylene Glycol) Dimethacrylate)-Nanofibrillated Cellulose as an Injectable Biomaterial Substitute for Herniated Nucleus Pulposus

Highlights: Novel synthetic biopolymer hydrogels were successfully prepared using photopolymerization method based on pristine PEGDMA and pristine NFC. Biocomposite hydrogel based on pristine PEGDMA: pristine NFC can be developed as a substitute biomaterial for the nucleus pulposus in cases of herniated nucleus pulposus which can afford for clinical application standards Abstract As many as 30-80% of cases low back pain (LBP) is frequently attributed to herniated nucleus pulposus (HNP) with 18-29% of instances reported in Indonesia. HNP can cause in motor weakness, sensory disturbances and decreased physiological reflexes. HNP occurs due to protrusion of the intervertebral disc through the annulus fibrosus which can be caused by the rupture of the annulus fibrosus or decreased proteoglycans (PGs). Hydrogel implant material is injected into the disc space, which can restore disc thickness caused by disc degeneration with minimal invasive. This study utilizes poly(ethylene glycol) dimethacrylate (PEGDMA):nanofibrillated cellulose (NFC) used to treat first-degree HNP using photopolymerization method. PEGDMA is very hydrophilic and is able to produce hydrogel. The addition of NFC to the PEGDMA precursor that forms a hydrogel was able to show mechanical properties as a hydrogel biocomposite candidate. This research to characterize of PEGDMA:NFC for biomaterial substitute of HNP. Characterizations involves Fourier Transform Infrared (FTIR) test, viscosity assessment and in vitro injection model test. PEGDMA:NFC concentrations explored include 1:0 (control), 1:0.5 (K1 sample), 1:0.75 (K2 sample) and 1:1 (K3 sample). FTIR test can indicating each functional group for hydrogel biomaterial of PEGDMA:NFC. Based on characterization results, the K3 sample has the best results with a concentration of 1:1. The viscosity value was 74,67 dPa.s and in vitro injection model test showed the addition of NFC indicates the hydrogel state when released from the mold will be not ruptured. Hydrogels can be injected with syringe 18 gauge. Consequently, the study concludes that the PEGDMA:NFC biocomposite hydrogel can be effectively applied in cases of herniated nucleus pulposus.

Preparation and properties of a newly developed devulcanized and pyrolytic crumb rubber modified asphalt

Purpose The purpose of this article is to determine the parameters of the preparation process for devulcanized and pyrolytic crumb rubber modified asphalt (DCRMA) and then study the rheological and microscopic properties of DCRMA through experiments.Design/methodology/approach In this study, a new preparation process for DCRMA was developed, then the penetration, softening point and viscosity tests were employed to determine the parameters of the preparation process. The crumb rubber (CR) solubility, Fluorescence microscopy (FM), Fourier Transform Infrared (FTIR) spectroscopy and thermogravimetric analysis tests were conducted to verify the devulcanized and pyrolytic effectiveness of the preparation process. Furthermore, dynamic shear rheometer and bending beam rheometer were used to characterize the high and low-temperature rheological properties of DCRMA.Findings The results showed that the penetration balanced the CR degradation and the virgin asphalt aging well and thus could be used as a main parameters control indicator. The CR solubility, FM and FTIR tests proved that the CR has been fully devulcanized and pyrolytic via the preparation process. The DCRMA exhibited better low-temperature and fatigue performance and lower rutting performance than the conventional crumb rubber modified asphalt (CRMA) with the same CR content. Finally, the time–temperature superposition principle could be employed for all binders in this study.Originality/value A new preparation process for DCRMA was developed.

The Effect of Titanium Dioxide Nanoparticle Composites as an Antibacterial in Synthesizing Polyurethane Biopolymers

Abstract. In the health sector, the use of polyurethane (PU) as a basic material for the manufacture of medical devices also creates problems related to local and systemic infections. One of the most appropriate ways to overcome this problem is to add titanium dioxide (TiO2) nanoparticles to the urethane polymer to produce a biodegradable polymer and bacterial decontamination. In synthesizing decontaminating polyurethane bacteria, several characterization techniques were carried out, including polymer test, namely strain and stress, functional group analysis using Fourier Transform Infra-Red (FTIR), and antibacterial test. Based on the results of the FTIR test analysis, shows a change in the functional group. At wave number 1724.36 cm-1, the N-H functional group appears, this absorption is the absorption of the urethane group and TiO2 is in the range of 513.07 cm-1. Mechanical properties test showed strain (28.92 - 21.88% GL) and young modulus at intervals (5,484-3,268 MPa). and the antibacterial test showed that the inhibitory power of test samples A1 and A4 with resistance diameters of 8mm and 8mm proved to be very effective in killing E.Coli bacteria while A1¹, A2¹, A3¹, and A4 killed could not kill S. Aureus bacteria inhibitors. The characterization results show that the polyurethane biopolymer can be used as a medical device with bacterial decontamination properties.

Critical considerations and effective assessment of extraction and recovery processes of RAP

With the increasing shortage of resources, the reuse of recycled asphalt pavements (RAP) in pavement engineering is considered as a sustainable technology. Challenges posed by common extraction and recovery methods may result in misjudgment of asphalt pavement performance. In this study, we investigate the optimization of extraction and recovery processes in recycled asphalt pavement (RAP) recycling, aiming to promote sustainable development within the pavement engineering sector. We prepared eleven asphalt samples to simulate common extraction and recovery scenarios, using virgin SBS-modified asphalt as a reference. Employing Fourier Transform Infrared (FTIR) analysis, thermogravimetric analysis (TGA), and Dynamic Shear Rheometer (DSR) testing, we assessed the samples' rheological and chemical properties. We pointed out three common but easily overlooked problems in the extraction and recovery process, namely residual mineral powder, residual trichloroethylene, and incomplete extraction. Residual mineral powder and trichloroethylene greatly influence extraction recovery accuracy; high-speed centrifugation effectively addresses trichloroethylene, but completely removing mineral powder remains challenging. Accurate evaluation of residual substances in recycled asphalt is achievable through FTIR, TGA, and rheological tests, providing valuable insights for material selection and processing. Additionally, it is crucial to fully recover the binder from RAP for precise performance evaluation, as the binder's interior exhibits lower aging levels compared to the surface. This aging heterogeneity should be considered when assessing RAP performance and developing effective rehabilitation strategies. Our findings hold significant implications for enhancing the efficiency and effectiveness of extraction and recovery processes in RAP recycling, ultimately contributing to sustainable development in pavement engineering.

Effect of silane coupling agent on the ultraviolet weathering behavior of polylactic acid based composites

Polylactic acid (PLA) is a promising material due to its biodegradability and compatibility. However, the limited resistance to ultraviolet (UV) degradation of PLA composites hinders their use in automotive interior materials. In our previous work, we successfully prepared 3D printed filaments by combining KH550-treated micro-nano rice husk (MNRH) fibers with KH570-treated PLA, which exhibited favorable performance. This study aimed to investigate the effects of silane coupling agents, MNRH, and accelerated UV weathering time on the photodegradation behavior of 3D printed PLA-matrix composites reinforced with MNRH. Scanning electron microscopy (SEM), Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) were utilized to characterize the 3D printed PLA-matrix composites. Furthermore, an exponential equation between tensile strength and UV weathering time was established, providing theoretical guidance for predicting the service life of automotive interior materials based on PLA composites. The morphological characterization experimental results indicate that with prolonged UV aging time, both PLA and RH6-KH550/KH570 composite materials transitioned from transparency to translucency. This transition can be attributed to the rupture of polylactic acid molecular chains and chemical bonds during the UV aging process. FTIR test results revealed the formation of carboxylic acid in the composite, and the reduction of C = O absorption intensity indicated that MNRH and silane coupling agents exhibited a stabilizing effect on the UV durability of the RH6-KH550/KH570 composite. TGA and DSC results indicated that KH550 and KH570 delayed the photodegradation rate of PLA-matrix composites.

Effect of the modification of a high-QI pitch with an additive on anode quality

Prebaked carbon anodes are manufactured from a dry aggregate (calcined petroleum coke, recycled butts, and rejected green and baked anodes) and a pitch as the binder. The process involves the mixing of the dry aggregate and the pitch according to an appropriate recipe followed by the compaction of the resulting paste and its baking to produce baked anodes for use in electrolysis cells for aluminum production. A good bonding between pitch and dry aggregate particles improves the anode quality which leads to reduction in process cost, energy and carbon consumptions, and emission of greenhouse gases (GHG). One of the potential avenues to improve such bonding is the modification of pitch by an additive. It enriches the surface functional groups of pitch and makes it more compatible with coke. The objective of the current study is to investigate the effect of the modification of a pitch containing a high amount of primary quinoline insolubles (HQI pitch) on the anode quality.The wettability of coke by modified and non-modified pitches was measured using the sessile drop method. Fourier Transform Infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses of these pitches were carried out to determine the change in their surface chemistry upon modification. Laboratory anodes were produced using the non-modified and modified HQI pitches at different pitch levels and additive percentages. The anodes were characterized by measuring their density, electrical resistivity, air and CO2 reactivities, and permeability. Then, these properties were compared for anodes containing non-modified (standard) and modified pitches. In general, the results showed that the modification improved the anode properties compared to those of the standard anodes. The most suitable additive percentage was 2 % and the best pitch percentage was 16 % to obtain good quality anodes. The wettability tests showed that the HQI pitch modified with 2 % additive wetted the coke best. XPS and FTIR tests showed the chemical changes occurring on the pitch surface after the modification with the additive. The results show the potential for the improvement of anode quality based on the pitch modification which renders pitch more compatible with coke.

Development and characterization of a copolymeric micelle containing soluble and insoluble model drugs.

Micelles are nano-sized particles with a core-shell structure that are made by natural or synthetic polymers or copolymers. The aim of this study was to develop and characterize a copolymeric micelle using two polymers loaded with hydrophilic and lipophilic drugs. Poly(ethylene glycol) and poly(ε-caprolactone) (PEG-PCL) were used to form a copolymeric micelle which was further loaded with either moxifloxacin or clarithromycin as hydrophilic and lipophilic drug samples, respectively. Characterization tests were done including fourier transform-infrared (FT-IR) spectroscopy, proton nuclear magnetic resonance (1H NMR) spectroscopy, encapsulation efficiency, particle size, zeta potential, polydispersity index, transmission electron microscopy, and in-vitro release test. The construction of the copolymer was confirmed by the results of FT-IR and 1H NMR spectroscopy tests. The encapsulation efficiency test exhibited that loading was about 50% for twelve formulations. Particle size, zeta potential, polydispersity index, and transmission electron microscopy confirmed the formation of monodispersed, uniform, and nano-sized micelles with a few negative charges. The kinetic model of release was fitted to the Higuchi model. Polymeric micelles consisting of PEG-PCL copolymer were loaded with adequate concentrations of hydrophilic (moxifloxacin) and lipophilic (clarithromycin) model drugs, with a mean particle size under 300 nm. Therefore, copolymeric micelles can be used as a suitable drug delivery system for mucous membranes and skin.

Simulation, design and synthesis of polybenzoxazine with different main‐chain structures and properties: A comparative study

AbstractIn order to explore effective strategies to fabricate main‐chain polybenzoxazine (PBZ) thermosetting resin for structural material applications, here, five PBZ with different molecular structures, that is, poly(Co‐ddm), poly(Co‐BPA‐ddm‐Co)main, poly(Ph‐BPA‐ddm‐Co)main, poly(Ph‐BPA‐ddm‐Ph)main and poly(Ph‐ddm) were designed, synthesized and compared by introducing unsaturated fatty chains through the Mannich reaction with cardanol. The structure and properties of five PBZ with different structure were systematically investigated by using Fourier transform infrared (FTIR), NMR, water absorption and mechanical tests. FTIR and NMR tests indicated that five PBZ with different molecular structures were successfully synthesized. The mechanical tests indicated that the impact strength of the double‐capped cardanol‐based main‐chain PBZ was 243% higher than that of the traditional PBZ. The water absorption of main‐chain PBZ was higher than that of diamine PBZ, and the water absorption of poly(Ph‐BPA‐ddm‐Co)main was the lowest in the main‐chain PBZ. Based on the experimental results, five PBZ amorphous cells with different structures were successfully established. It indicated that the main chain PBZ showed better thermomechanical properties than the traditional diamine PBZ due to high crosslinking conversion and hydrogen bond density. Moreover, the modulus and glass transition temperature of the main chain structure containing unsaturated fatty chains did not decrease significantly.

Monitoring surface dynamics of electrodes during electrocatalysis using in situ synchrotron FTIR spectroscopy.

Monitoring the surface dynamics of catalysts under working conditions is important for a deep understanding of the underlying electrochemical mechanisms towards efficient energy conversion and storage. Fourier transform infrared (FTIR) spectroscopy with high surface sensitivity has been considered as a powerful tool for detecting surface adsorbates, but it faces a great challenge when being adopted in surface dynamics investigations during electrocatalysis due to the complication and influence of aqueous environments. This work reports a well designed FTIR cell with tunable micrometre-scale water film over the surface of working electrodes and dual electrolyte/gas channels for in situ synchrotron FTIR tests. By coupling with a facile single-reflection infrared mode, a general in situ synchrotron radiation FTIR (SR-FTIR) spectroscopic method is developed for tracking the surface dynamics of catalysts during the electrocatalytic process. As an example, in situ formed key *OOH is clearly observed on the surface of commercial benchmark IrO2 catalysts during the electrochemical oxygen evolution process based on the developed in situ SR-FTIR spectroscopic method, which demonstrates its universality and feasibility in surface dynamics studies of electrocatalysts under working conditions.

Characterization of Polyvinyl Alcohol-Collagen-Hydroxyapatite Composite Membrane from Lates calcarifer Scales for Guided Tissue and Bone Regeneration.

To determine the chemical structure, tensile strength, porosity, and degradability of polyvinyl alcohol (PVA)-collagen-hydroxyapatite (HA) composite membranes for guided tissue and bone regeneration. The PVA-collagen-HA composite membrane was divided into three groups: the group without irradiation, the group with 15 kGy irradiation, and 25 kGy irradiation. Each group was tested for chemical structure with Fourier-transform infrared (FT-IR) at a wavelength of 400 to 4,000 cm-1. Tensile strength test was tested in dry and wet conditions with the standard method of American Standard Testing Mechanical (ASTM) D638, and porosity using scanning electron microscope and analyzed using ImageJ software. Degradability test immersed in a solution of phosphate-buffered saline. Data were analyzed using analysis of variance (ANOVA) and Tukey's test. FT-IR test before and after storage for 30 days on three media showed a stable chemical structure with the same functional groups. ANOVA analysis showed a significant difference (p < 0.05) in the dry condition (p = 0.006), Tukey's test showed a significant difference in the 15 kGy and 25 kGy irradiated groups (p = 0.005), but the groups without irradiation had no significant difference with the 15 kGy (p = 0.285) and 25 kGy (p = 0.079) irradiation groups. In wet conditions, there was no significant difference (p > 0.05) in each group (p = 373). The size of the porosity in the group without irradiation, 15 kGy irradiation, and 25 kGy irradiation showed a size of 4.65, 6.51, and 8.08 m, respectively. The degradability test showed a decrease in weight in each group, with the total weight of the membrane being completely degraded from the most degraded to the least: the groups without irradiation, 15 kGy irradiation, and 25 kGy irradiation. The ANOVA test on the degradability test shows significant (p < 0.05) in the PVA-collagen-HA composite membrane group over time intervals (p = 0.000). Tukey's post hoc test showed a significant difference (p < 0.05) after 1 week between the groups without irradiation with 15 kGy (p = 0.023). PVA-collagen-HA composite membrane has a stable chemical structure, optimal tensile strength, porosity, and ideal degradability as guided bone regeneration and guided tissue regeneration.

Potential of pomegranate seed powder as a novel natural flocculant for pulp and paper wastewater treatment: Characterization, comparison and combination with alum

Using natural flocculants for water and wastewater treatment through coagulation-flocculation process has received growing attention due to its simplicity and safety process. In this research, the performance of pomegranate seed powder as a novel natural flocculant in treating pulp and paper wastewater (PPWW) was evaluated. Chemical oxygen demand (COD) reduction and turbidity removal from PPWW were monitored using different dosages of pomegranate seeds and alum salt. In addition, the synergistic effect of dual flocculation between pomegranate seeds and alum on PPWW treatment was investigated and optimized. Zeta potential (ZP), Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) analyses were conducted to elucidate the flocculation mechanism. The results revealed that pomegranate seeds composed of active substances such as protein, polysaccharides and fiber contents that contribute to its coagulating ability. The highest removal efficiencies of 60% and 87% were achieved for COD and turbidity, respectively when using pomegranate seeds at the optimal dosage of 600 mg/L after 30 min treatment. Dual flocculation of pomegranate seeds and alum showed a synergistic effect, resulting in a maximum removal of 81% of COD and 98% of turbidity under optimal condition: Alum = 400 mg/L and pomegranate seeds = 800 mg/L at much shorter treatment time (2 min). The ZP and FTIR test results and SEM images revealed that charge neutralization and sweeping mechanism induced by alum combined with bridging mechanism by pomegranate seeds led to the synergy.

Selective Adsorption of Sodium Silicate on the Surface of Bastnaesite and Fluorite in Salicylhydroxamic Acid System under Alkaline Conditions

During the flotation separation process of bastnaesite, it is difficult to separate bastnaesite from fluorite effectively. In this present study, sodium silicate (SS) can effectively improve the flotation separation effect of bastnaesite and fluorite in salicylhydroxamic acid (SHA) systemasa. Through relevant analyses, such as Zeta potential measurements, adsorption capacity tests, Fourier transform infrared (FTIR) spectroscopic analyses and X-ray photoelectron spectroscopy (XPS) tests, the selective suppressor of SS on fluorite was proven. At pH 10, the single mineral flotation results show that with the increase of SS dosage, the flotation recovery of fluorite rapidly decreases from 61.5% to 35.31%, while the flotation rate of bastnaesite is still high (recovery is 80.02%). Then, the experiment of artificial mixed ore proved that the flotation separation of fluorite and bastnaesite was effective under the appropriate dosage of inhibitor. The results of potentiodynamic measurement and an adsorption capacity test showed that the SiOOH3− structure of SS more easily reacted with fluorite, which further prevented the adsorption of SHA on the fluorite surface. FTIR test results and XPS analysis further showed that SS had a strong binding effect with the Ca site on the fluorite surface, but a weak binding effect with the Ce site on the bastnaesite surface. Consequently, SS can be used as an effective inhibitor in the flotation separation of fluorite and bastnaesite.

PENYISIHAN LOGAM CR (VI) DARI LIMBAH CAIR ELEKTROPLATING MENGGUNAKAN ADSORBEN BEADS KOMPOSIT CHITOSAN-CLAY

Water pollution by heavy metals is a serious problem. One of the dangerous parameters that contaminate waters is heavy metals that come from metal industrial waste. Electroplating wastewater contains heavy metals that are harmful and toxic to the environment. Alternative treatment that can be used is the adsorption process with a column system using chitosan-clay beads. Chitosan has amine and hydroxyl groups which have ability to absorb heavy metals. The results of the characterization by FTIR (Fourier Transform Infrared) test on chitosan produced contained a chitosan functional group and obtained a DD value of 80.97%. This study aims to remove Cr (VI) in electroplating wastewater. The variations carried out were variations in the ratio of the composition of chitosan-clay beads (w/w) (1.5:1), (2:1), (2.5:1) and a flow rate 3 mL/minute; 3.5 mL/min; and 4.5 mL/min. The results of the water absorption test (DSA) obtained for each variation of chitosan-clay beads were 609.52%; 628.27%; 658.04%, and the results of the compressive strength test are 22.491; 10,653; 3,015 Kgf. The results obtained are the best Cr (VI) removal efficiency of 95.46% with concentration of Cr (VI) 1.1566 mg/L at the ratio of chitosan-clay beads composition (2,5:1) (w/w) and flow rate 3 mL/min.

Mechanical properties and conductivity of polyaniline-cellulose-latex hybrid

Composite films of polyaniline (PANI)-cellulose and prevulcanised latex (PVL) were prepared and studied extensively to understand the impact on mechanical properties and conductivity. PANI promotes conductive properties in any host matrix to form blends or composites. Usage of cellulose was intended to supplement the poor mechanical properties showed by PANI and further improve composite films. Alpha cellulose (AC) and microcrystalline cellulose (MCC) were applied to elucidate the significant effect of different particle size of celluloses. PANI-AC and PANI-MCC templates were synthesized through chemical oxidative polymerization with sodium dodecyl sulphate (SDS) as surfactant and mixed with PVL in different concentrations. Films were obtained by casting method and characterized by FTIR (Fourier Transform Infrared), TGA (Thermogravimetric Analysis) and tensile test. The results revealed that these templates improved the mechanical performance of PVL at 3 g and 5 g loading but further increase the loading led to a declining trend. The TGA revealed that increasing the amount of PANI-AC and PANI-MCC loading in PVL resulted in improved conductivity.

Multi-Scale Characterization of High-Temperature Properties and Thermal Storage Stability Performance of Discarded-Mask-Modified Asphalt

In the context of the global pandemic of COVID-19, the use and disposal of medical masks have created a series of ethical and environmental issues. The purpose of this paper is to study and evaluate the high temperature properties and thermal storage stability of discarded-mask (DM)-modified asphalt from a multi-scale perspective using molecular dynamics (MD) simulation and experimental methods. A series of tests was conducted to evaluate the physical, rheological, thermal storage stability and microscopic properties of the samples. These tests include softening point, rotational viscosity, dynamic shear rheology (DSR), Fourier transform infrared (FT-IR) spectroscopy and molecular dynamics simulation. The results showed that the DM modifier could improve the softening point, rotational viscosity and rutting factor of the asphalt. After thermal storage, the DM-modified asphalt produced segregation. The difference in the softening point between the top and bottom of the sample increased from 2.2 °C to 17.1 °C when the DM modifier admixture was increased from 1% to 4%. FT-IR test results showed that the main component of the DM modifier was polypropylene, and the DM-modified asphalt was mainly a physical co-blending process. MD simulation results show that the DM modifier can increase the cohesive energy density (CED) and reduce the fractional free volume (FFV) of asphalt and reduce the binding energy between base asphalt and DM modifier. Multi-scale characterization reveals that DM modifiers can improve the high temperature performance and reduce the thermal storage stability of asphalt. It is noteworthy that both macroscopic tests and microscopic simulations show that 1% is an acceptable dosage level.

Pengaruh Komposisi Kitosan Terhadap Sifat Fisis Dan Biodegradable Film Komposit Nanoserat Pinang Dengan Castor Oil Sebagai Plasticizer

Research has been carried out on the effect of chitosan composition on the physical and biodegradable properties of areca nut nanofiber composite films with castor oil as a plasticizer. Samples were made using the solution casting method. The variations of chitosan used were 0 g, 0.56 g, 0.7 g, 0.84 g, 1.4 g and one sample used starch with a variation of 0.84 g chitosan. The physical properties of the samples tested were thickness test, FTIR test and FESEM test. Mechanical properties tests include tensile strength, elongation, elasticity, and biodegradation tests. The samples were characterized using a Particle Size Analyzer (PSA) to determine the size of the nanofibers, a Field Emission Scanning Electron Microscope (FESEM) to determine the sample morphology and Fourier Transform Infrared (FTIR) to determine the functional groups. PSA results showed that the nanofibers had a diameter of (79-187) nm. The results of FESEM characterization obtained the shape of a hollow biodegradable plastic surface. The FTIR results indicate the presence of a C=O functional group and C-O is a hydrophilic functional group which indicates that biodegradable plastic is capable of being degraded. The best tensile strength results in the chitosan variation of 0.84 g without starch with a value of 20.04 MPa, the best elongation in the 0.7 g chitosan variation with a value of 138.56%, elasticity 198.66 MPa in the 0.84 g chitosan variation with the addition of starch, the average thickness is 0.25 mm. The higher the variation of chitosan, the thickness, tensile strength, elasticity, and biodegradation of biodegradable plastics increase, while elongation decreases