H3 Hysteresis Loop Research Articles

Characterization of geochemical properties and factors controlling the pore structure development of shale gas reservoirs

The pore structure is an important parameter to understand the transport and storage capacities in shale. There is very limited research reported on the controlling factors of pore development in lacustrine shales to date. This study investigated pore developments and hydrocarbon generation potential of lacustrine Roseneath and Murteree shale formations. Although these shale formations are proven shale gas reservoir in the Cooper Basin, Australia, pore development studies are still rare. The geochemical properties measured on core samples include total organic contents (TOC), thermal maturity, hydrocarbon generation potential, and mineral composition by X-ray diffraction (XRD). Field-emission scanning electron microscopy (FE-SEM), Focused Ion Beam milling scanning electron microscopy (FIB-SEM), and low-pressure nitrogen adsorption-desorption isotherm experiments were used to quantify and qualify pore structure. Furthermore, the factors were analyzed that control pore development through statistical analysis. The results indicate that organic contents for the Roseneath shales (0.9%–1.74% Ro%) and Murteree shales (1%–1.7% Ro%) range between 0.81% and 5.36% and 0.51%–6.69%, respectively. The dominant mineral phases are quartz, clay (Illite, Kaolinite), and siderite, with variable quantities of the studied formations. Rock-Eval pyrolysis suggests Kerogen Type III and implies mostly late oil generation to dry gas generation potential in both shale formations. In Roseneath shale, total surface area (SSA) and total pore volume (TPV) varies from 2.25 cm2/g to 5 cm2/g and 0.005 cm3/g – 0.02 cm3/g, respectively. In Murteree shale, SSA and TPV vary from 3.5 cm2/g to 6.35 cm2/g and 0.005 cm3/g to 0.032 cm3/g, respectively. The pores exhibit unimodal to bimodal distribution with peaks at 2–4 nm, 90–120 nm, and 170–180 nm. The mesopores are dominant in studied formations, followed by macropores and micropores. Mesopores have the largest contribution to specific surface area and pore volume. The desorption hysteresis loop on the N2 adsorption-desorption curve indicates the presence of permeable and impermeable pores, as most of the samples belong to H2 and H3 type hysteresis loop. The pore size of intraparticle and interparticle various greatly; however, the pores with a diameter of 2.5 nm, 18 nm and 49 nm are common in both formations. The organopores contribute to micropores' development, and most organic pores have a pore diameter of 1.5 nm and 1.8 nm. The total pore volume (TPV) and specific surface area (SSA) are positively correlated with organic matter contents, quartz, and thermal maturity in both shale formations. However, clay minerals are positively correlated with SSA and TPV, which indicate that clay minerals have a significant contribution to Roseneath shale's pore development. The siderite mineral contributes to intraparticle pores development and positively correlated with SSA and TPV in Murteree shale. The thermal maturity significantly enhances pore's development by creating organopores and inorganic pores in both shales, as evidenced through statistical analysis and image analysis. The study has significant importance in understanding the pore structure and gas storage mechanism in shale.

The organic geochemistry, pore structure and methane adsorption/storage capacity of lacustrine shales from the Cretaceous Madongshan Formation, Liupanshan Basin, China

Lacustrine shale from Madongshan Formation in Liupanshan basin has been the important target strata for shale gas exploration in northwest China. However, the system cognition in generation, reservoir conditions and geological gas-in-place (GIP) estimation of Madongshan shale is quite limited. In this research, the shale strata are evaluated in terms of shale quality, pore structure and methane adsorption/storage capacity. The results show that Madongshan shales mainly belong to mixed mudstone and siliceous mudstone and have the relatively high brittle minerals content and low clay minerals contents, indicating a favorable condition for hydraulic fracturing. The Rock-Eval pyrolysis reveals that the shales can be classified as good to very good to source rock with relatively high TOC over 2% and contain type Ⅰ and Ⅱ kerogen in the early maturation stage with a fixed amount of gas can be produced. In terms of pore structure, the Type IV isotherms and Type H3 hysteresis loops of shale samples show that mesopores and macropores with slit-like pore types are the dominated space in Madongshan shales. The maxima of methane adsorption capacity (n0) ranged from 2.32 ml/g to 5.96 ml/g are significantly by organic matters and clays. Despite the relative importance of organic carbon to methane adsorption capacity, influence of TOC on pore surface area and volume is negative interaction, perhaps reflecting the dissolution of methane in the residual bitumen. Thus, an assessment on lacustrine shale gas with low maturity needs to consider the influences of solute methane in residual bitumen, apart from adsorption methane, so as to obtain a reliable shale gas resource. The clays show a complex relationship of influence on n0 and it may be related to the pore structure and the difference of methane capacity between clays and organic matters. At last, a modified and simpler equation which can eliminate the errors is adopted to calculate the methane storage capacity of Madongshan shales. And the methane storage capacities of Madongshan shales range from 2.06 ml/g to 2.16 ml/g.

Ascorbic acid-assisted hydrothermal route to create mesopores in polymeric carbon nitride for increased photocatalytic hydrogen generation

The facile synthesis of mesoporous polymeric carbon nitride (PCN) can enlarge the surface area and provide mass transport channels, which thus potentially boosts its photocatalytic H2 generation. However, the formation of mesopores in PCN are mainly relying on the hard and soft templates with tedious operations, and it remains a grand challenge in preparing mesoporous PCN without the assistance of templates. Herein we report on an ascorbic acid-assisted hydrothermal route to effectively create the mesoporous in bulk PCN. The mesopores thus formed a typical IV isotherm with an H3 hysteresis loop, and have a pore size distribution of ∼3.8 nm. Moreover, the crystallinity of mesoporous PCN was improved with ascorbic acid-assisted hydrothermal treatment. Meanwhile, ascorbic acid can be converted to carbon materials under hydrothermal conditions. As a result, an increased photocatalytic H2 generation was realized under visible light exposure. The highest H2 generation rate is up to 26.8 μmol h−1 for Pt/CN-A10%, near 10 times higher than that of Pt/PCN (2.7 μmol h−1). This work highlights the effectiveness of organic acid-assisted hydrothermal treatment for synthesizing mesoporous PCN for increased photocatalytic performance.

Mutual inhibition effect of sulfur compounds in the hydrodesulfurization of thiophene, 2-ethylthiophene and benzothiophene ternary mixture

The hydrodesulphurization of a model component and equimolar ternary mixture of thiophene, 2-ethylthiophene and benzothiophene over sulphided CoMo/γ-Al2O3 and CoMo/γ-Al2O3-Nb2O5 catalysts were investigated in a fixed bed flow reactor. The catalysts were prepared by incipient wetness impregnation method and characterized by textural characteristics, total acidity and chemical species present on the catalysts surface. The characterization results showed that both CoMo/γ-Al2O3-Nb2O5 and sulphided CoMo/γ-Al2O3 catalysts exhibit a mesoporous structure with cylindrical pores open at both ends, evidenced by the IV type adsorption–desorption isotherm with a H1 hysteresis loop and have an average pore diameter between 3 and 4 nm. The chemical species present on the catalysts surface evaluated by XPS indicated that Co2+ and Mo4+ species are present in the sulfide form on both catalysts surfaces. In addition, there are also found oxidic species arising from incomplete reduction and sulphidation. The presence of niobium oxide in the catalytic support had a positive effect in leading to higher specific surface area (170 m2/g) and total acidity (0.421 meq/g) compared with CoMo/γ-Al2O3 catalyst (140 m2/g and 0.283 meq/g) respectively. The evaluation results from the hydrodesulfurization showed that CoMo/γ-Al2O3-Nb2O5 catalyst had a higher activity in hydrodesulphurization process of thiophene, 2-ethylthiophene and benzothiophene. The CoMo/γ-Al2O3-Nb2O5 catalyst eliminated sulfur from the single component feed (corresponding to 2380 ppm S) and reduced below 10 ppm, for the feed consisting in the equimolar ternary mixture of thiophene, 2-ethylthiophene and benzothiophene (2380 ppm S). The reactivity of thiophen compounds was reduced due to competitive adsorption. It was observed that benzothiophene inhibits the transformation of thiophene and 2-ethylthiophene. A mutual inhibition effect between sulfur compounds was also observed when thiophene, 2-ethylthiophene and benzothiophene were combined and tested over the CoMo/γ-Al2O3 catalyst. The inhibition effect had a lower intensity by introducing Nb2O5 in the catalyst support.

Three-dimensional bundle-like multiwalled carbon nanotubes composite for supercapacitor electrode application

Bundle-type mutil-walled carbon nanotubes (MWCNTs) composite electrode is the first investigation and publication for the supercapacitor application. According to the thermogravimetric analysis results, as-synthesized BCNTs are considered as the electrode materials for supercapacitors and electrochemical double-layer capacitor in this study. The Brunauer–Emmett–Teller specific surface area of as-prepared bundled carbon nanotubes (BCNTs) is 95.29 m2/g given to a type III isotherm and H3 hysteresis loops. Slow scanning rates promote and enhance to achieve high Cb because of the superior conductivity of CNT bundles and one side close-layered Ni/Mg/Mo alloy inside the BCNT-based electrode and facile electron diffusivity between electrolyte and electrode. The specific capacitance Cs (1,560 F/g) is nearly equal to the maximum specific capacitance, which the BCNT-based composite electrode can actually be able to charge or fill in. The maximum energy density value is 195 Wh/kg with corresponding power density values of 0.21 kW/kg. Furthermore, the active 3D BCNTs material fabricated electrode enhances to contact the electrolyte directly and decreases the ion diffusion limitation. Electrochemical impedance spectroscopy spectrum summarized as the low-frequency area controls by mass transfer limitation, and the high-frequency area dominates by charge transfer of kinetic control. After 2,000 consecutive cyclic voltammetry sacnings and galvanostatic charge-discharge cycles at a current density of 1.67 A/g performs, the specific capacitance retentions of 3D BCNTs electrodes achieved 128.2 and 77.3%, respectively. Three-dimensional BCNT composite electrodes exhibit good conductivity and low charge transfer resistance, which is beneficial to fast charge transfer between the BCNTs electrode materials and electrolytes.

A simple, step-by-step approach for the preparation of MoO3@g-C3N4 nanocomposite

We present a simple step-by-step method for the preparation of MoO3@g-C3N4 nanocomposite. Several approaches were used to prepare and characterize the nanocomposite with a weight ratio of MoO3 (0.075). X-ray diffraction measurements have revealed The primary peaks of MoO3 at 13.14°, 23.74°, 26.07°, 27.71°, 29.98°, and 39.33° correspond to the iq (020), (110), (040), (120), (021), and (060) planes, and the g-C3N4 appearing at 27.49° and 12.94° corresponds to the (002) and (100) planes in the MoO3@g-C3N4 nanocomposite. The specific bands for the as-prepared nanocomposite were revealed by Fourier-transform infrared. With the H3 hysteresis loops, the BET isotherm and the BJH technique produced results compatible with Type IV. Furthermore, the results indicated the effective change in surface area, pore-volume, and pore diameter values were larger in the MoO3@g-C3N4 nanocomposite. Diffuse spectroscopy of reflection data revealed more information about the changes that occurred when MoO3 was loaded on the g-C3N4 layers to shift the spectrum to the red extent while decreasing the band gap to 2.63 eV. Furthermore, field emission electron spectroscopy has proven the synthesis of nanocomposite by a dramatic change in the morphological surface as well as a change in the composition of elements that have been demonstrated using the energy-dispersive X-ray spectroscopy methodology. This discovery has improved the form and structure of the MoO3@g-C3N4 nanocomposite

Synthesizing nanocomposite TiO2@ZnFe2O4 using a simple one-pot solvothermal technique

This paper reports solvothermically the synthesis of TiO2@ZnFe2O4 nanocomposite. It was synthesized and characterized by several procedures with a weight ratio of 2 percent. X-ray diffraction tests were detected at 24.45° to show the typical weak peaks in TiO2@ZnFe2O4, confirming TiO2 (anatase) at 30.10°, 35.47°, 41.06°, 45.64°, 56.64° and 62.51°, which represent a characteristic peak of the ZnFe2O4 - orientations (220), (311), (400), (422), (511) and (440), respectively. The nanocomposite has been found to have significant peaks at 311° and 411°. The preparation of TiO2@ZnFe2O4 nanocomposite is confirmed by Fourier-transform infrared. FESEM was also conducted to analyze TiO2@ZnFe2O4’s shape and structure. In addition, information in line with IUPAC type III and the H2 hysteresis loops were provided by the BET isotherm and the BJH technique. In the surface, pore-volume, and pore diameter, the findings have supported effective changes. Diffuse reflection spectroscopy gave more information on the modifications that occurred in the nanocomposite to alter the spectrum to the red region while reducing the band gap to 1.65 eV. These findings have strengthened the structure of nanocomposite as-prepared.

Mesoporous Silica Nanoparticle-Templated Ionic Liquid as a Drug Carrier for Ibuprofen and Quercetin

In this study, a series of mesoporous silica nanoparticle (MSN) was successfully synthesized using different ionic liquids (ILs) as a template. Five ILs and a surfactant with different alkyl side chains and types of anion namely 1-dodecyl-3-methylimidazolium iodide ([C12mim][I]), 3-diethylamino propanol vanillate (DV), 2-butylamino ethanol salicylate (BS), 3-diethylamino propanol salicylate (DS), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([bmim][NTf2]) and hexadecyltrimethylammonium bromide (CTAB) were used. All MSNs produced have broad peaks, indicating mesoporous silica in amorphous form as observed by XRD while the morphology of MSN showed the agglomeration of particles and due to parallel arrangement pores size in both for FESEM and HRTEM. The MSNs are amorphous and displayed Type IV BET isotherm with H2 hysteresis loops which is a typical isotherm for mesoporous materials and the highest surface area obtained was 638 m2/g. The study on uptake and release of ibuprofen and quercetin were carried out, where ibuprofen showed higher drug uptake compared to quercetin due to better interaction of MSN with drug molecules. The drug release conducted at 48 h indicates 33.1% of ibuprofen and 38.4% quercetin released. It can be indicated that MSN-BS is the best for drug loading and release. Drugs release kinetics study indicated that the release process follows the Korsmeyer peppes model. The best efficiency of drug loading for MSN-BS/IBU and MSN-BS/QUE was at 48 h and 25 °C with 250 rpm stirring rate for both IBU and QUE, respectively.

Physical properties and structural characteristics of alkali modified fly ash

Fly ash as residue from coal combustion has potential for environmental applications as an adsorbent for water pollution treatment. Adsorption performance of fly ash depends on fly ash origin and chemical treatment. Modification by the chemical treatment could increase the adsorption capacity. In this paper, fly ash was alkali modified with NaOH solution at various concentrations (2 N, 4 N, 6 N, 10 N) at a temperature of 60 °C. The physical properties and structural characteristics of unmodified fly ash and alkali modified fly ash were studied from Brunauer-Emmett-Teller (BET) surface area and pore size analysis, and also scanning electron microscope (SEM) analysis. The results showed that alkali modification could increase surface area, average pore radius, and total pore volume in fly ash. Unmodified fly ash and alkali modified fly ash could be classified as mesoporous materials and exhibited type IV nitrogen adsorption-desorption isotherms with H3 hysteresis loop according to the classification of the International Union of Pure and Applied Chemistry (IUPAC). SEM observations revealed that modified fly ash had rougher surface and more porous structure than that of unmodified fly ash. Alkali modification had changed the physical properties and structural characteristics of fly ash that supports its application as an adsorbent.

Preparation of Hollow Silica Nanoparticles Using Fluorinated Surfactant and Fluorocarbon Solvents

In this study, we used a new class of fluorinated surfactant as a soft template for the preparation of the hollow silica nanoparticles. The size of the hollow silica nanoparticles was enlarged by incorporating a variety of swelling agents (perfluorodecalin, perfluorotributylamine, perfluorooctane, and perfluorooctyl bromide) into the cores of the micelles of the fluorinated surfactant. However, once we used the perfluorinated acids (perfluorooctadecanoic acid and perfluorodecanoic acid) as swelling agents, the structure of silica nanoparticles is solid without the formation of hollow voids. The TEM analysis combined with copper elemental mapping of the hollow silica loaded with copper hexadecafluorophthalocyanine indicated that the cores of the hollow silica nanoparticles are hydrophobic. The formation mechanism of the hollow silica nanoparticles is similar to that prepared by hydrocarbon surfactant/hydrocarbon, which was supported by the zeta potential measurements. The prepared hollow silica nanoparticles had the type IV isotherm with the H3 hysteresis loop.

Ammonia storage/release behaviors of the CeSn0.2Mo0.6Ox/TiO2 catalyst in selective catalytic reduction of NO

• CeSnMoO x /TiO 2 obtained stable NO removal due to ammonia storage/release. • Excess NO induced ammonia release, the amount reached maximum during 250−300 °C. • Ammonia was mainly stored in physical form and partly by chemical adsorption. • High temperature enhanced ammonia activation and improved ammonia release. This work explored the ammonia storage/release behaviors of the CeSn 0.2 Mo 0.6 O x /TiO 2 catalyst in selective catalytic reduction of NO. Results displayed that the CeSn 0.2 Mo 0.6 O x /TiO 2 performed much higher NO removal rate than the theoretical maximum if the NH 3 /NO ratio was lower than one, which was due to the ammonia storage/release behaviors. The ammonia storing was more likely to occur at low temperatures, and the storage capacity of the catalyst reached 27 μmol m −2 at 50 °C. Moreover, ammonia exists mainly on physical form of temperatures below 250 °C and is adsorbed in weakly acidic sites; while high temperature strengthen activation of strong acid sites, resulting in increasing the ammonia storage at 350 °C. NH 3 -TPD results showed two peaks of ammonia desorption, indicating the weak and strong acid sites of the catalyst. The ammonia storage/release curves at Constant Temperature Flow Field were asymmetric and BET isotherm showed Type H3 hysteresis loop, which was caused by mass transfer in the plate-like pore structure formed by the particle polymerization. The porous structure and highly dispersed active components were beneficial for storing ammonia. The effective utilization ratio of the stored ammonia decreased with the increasing temperature and GHSV.

A dual shape pore model to analyze the gas adsorption data of hierarchical micro-mesoporous carbons

Hierarchical micro/mesoporous carbons obtained by template carbonization were investigated by nitrogen adsorption/desorption and gave a type IV isotherm with a H1 hysteresis loop closing perfectly near P/P0 = 0.6. When using the 2D-NLDFT theory to calculate the pore size distribution (PSD) from the adsorption branch of the isotherms, while assuming slit pores with a heterogeneous rough surface (2D–HS–SLIT model), an unexpected artifact was observed ca. 3.5 nm. Recognizing that the H1 hysteresis loop is usually related to the adsorption in materials with cylindrical pores, where in general it is recommended to use the desorption branch for the pore size analysis, we have applied the 2D–HS–SLIT model to the adsorption isotherm up to P/P0 = 0.2 and a cylindrical pore model to the desorption isotherm down to P/P0 = 0.2. Interestingly, the application of this dual shape pore model to hierarchical micro/mesoporous carbons of various mesopore sizes and oxygenated surface functionalities shows an excellent fit with the experimental isotherms, while the mesopore peak in the PSDs is narrower, and the previously labeled artifact is eliminated. It is noteworthy that the cumulative surface area values are significantly larger than when applying the 2D–HS–SLIT model, what is due to the larger surface area of cylindrical than slit-shaped mesopores.

Experimental and Fractal Characterization of the Microstructure of Shales from Sichuan Basin, China

Comprehensive characterization and analysis of the microstructure characteristics of shale are significant for understanding its transport mechanisms and determining highly efficient production programs. In this study, composition analysis, scanning electron microscopy imaging, and gas adsorption–desorption measurements are first conducted on 29 marine shale samples from the Longmaxi Formation, Sichuan Basin, China, to obtain their petrophysical properties and microstructure characteristics. Then, surface fractal dimension, pore fractal dimension, lacunarity, and succolarity are introduced to analyze the microstructure of these shale samples. Finally, the correlations between total organic carbon (TOC) content and microstructures and the relationships among the microstructures are analyzed systematically. The results show that the complex pore network in these shales is constituted by microfractures, intergranular pores, intragranular pores, dissolved pores, and organic pores. The typical type IV adsorption isotherm and type H3 hysteresis loop are identified from nitrogen adsorption–desorption data. TOC content has positive influences on the adsorption capacity and nanopore distribution. The surface fractal dimensions under low and high relative pressure are similar in these marine shale samples, which is different from the two-section characteristic of continental and marine-continental shale. The statistical self-similarity characteristic of the pore-size distribution in these shales is further confirmed based on the analytical fractal dimension equation. The normalized lacunarity can quantitatively characterize the heterogeneity of the pore-size distribution of these shales in two-dimensional space. The succolarity analysis in two-dimensional space explains the low fluid transport capacity of these shales. Universal and logically explained correlations are found between TOC content and microstructures. Moreover, logically explained correlations also exist among the microstructures of the shale samples evaluated.

Non-calcined ZrO2 sol-coated hollow glass fibre membrane: Preparation, microstructure, and dye separation

In this work, a hollow glass fibre membrane was prepared and coated with a ZrO2 sol by dip coating. The ZrO2 sol coating adhered to the pristine membrane through interfacial interactions, as determined by FTIR spectroscopy and XPS analyses. The N2 adsorption-desorption curves indicated that the pores of the pristine and coated membranes formed by the accumulation of glass powder and ZrO2 sol layers, as determined from the H1 and H4 hysteresis loops, respectively. Thin and dense coating layers were observed on the surface of the coated membranes. Contact angle measurements showed that the hydrophilicity of the coated membranes remained almost constant. Furthermore, compared with the pristine membrane, the coated membranes exhibited higher rejection. The water flux and rejection varied within a narrow range even when separation was performed using the coated membrane for 12 h. The coated membrane with long-term stability demonstrates a good application prospect for highly efficient wastewater treatment.

One-step statistical design of experiment for the screening and optimization of magnetite nanoparticles yields from solvothermal synthesis

One-step custom design of experiment was employed for the simultaneous screening and optimization of raw yield (Y 1 ) and percent yield (Y 2 ) with heating temperature, T (190–220 °C) and reaction time, t (1.0–2.5 h) as the predictors in a conventional solvothermal magnetite nanoparticles (NPs) synthesis. Two accurate models capable of explaining 98.3% variability in the data were developed. A strong correlation exists between the actual yields (Y 1 , Y 2 ) and their predicted counterparts (r = 0.99). T, t, Tt and t 2 terms have a significant synergistic effect on the yields the at α = 0.05. The diagnostic plots depicted the effects in the order t > T > Tt > t 2 . Surface and contour plots show maximum Y 1 (0.295 g) and Y 2 (105%) at T = 219 °C and t = 2.5 h. The optimizer plot shows maximized Y 1 (109.94%) and Y 2 (0.31 g) at the highest predictor values (T = 220 °C, and t = 2.5 h) at composite desirability of 1. NPs characterization using various techniques revealed nanocubes and nanospheres with a mean diameter of 23.9 ± 7.9 nm, the crystallite size of 8.3 ± 1.4–20.4 ± 4.9 nm, a pore size of 9.07–24.47 nm, and surface area of 35.80–93.57 m 2 g −1 . The NPs exhibit stretching Fe–O vibrations at 571 cm −1 for tetrahedral and at 428 cm −1 for octahedral geometries in the infrared spectra and are thermally stable within the range 30–700 °C with low weight loss (8.81–32.92%) typical of mesoporous magnetite phase. • Response models explain 98% variability in the 16.4-nm mean sized Fe 3 O 4 NPs yields. • Diagnostic charts depict the significance of time and temperature effects on yields. • Fe 3 O 4 NPs yields are maximized at 220 °C, 2.5 h and composite desirability of one. • Most Fe 3 O 4 NPs samples exhibit H1 hysteresis loop and Type IV adsorption isotherm.

Photocatalytic performance mesoporous Nd2O3 modified ZnO nanoparticles with enhanced degradation of tetracycline

This contribution reports the synthesis of mesoporous X% Nd2O3 modified ZnO (X = 1, 2, 3 and 4) during sol-gel process in existence of Pluronic F-108 for the first time. XRD indicated the construction of hexagonal ZnO nanocrystals and the isotherms exhibited of type IV with a type H2 hysteresis loop, indicating the existence of mesostructures. The synthesized samples were evaluated by photodegradation of tetracycline (TC) in visible light exposure compared to pure mesoporous ZnO nanoparticles (NPs) and commercial photocatalyst P-25. The photocatalytic efficiency mesoporous 3%Nd2O3/ZnO for degradation TC reached up to 100 % for 2 h compared to pure mesoporous ZnO and P-25 with 4 and 10 %, respectively. The mesoporous 3%Nd2O3/ZnO photocatalysts showed promoted photocatalytic performance, resulting in an improved photodegradation rate value up to 8.8 and 16.3 times that of compared to pure ZnO and P-25, which was explained by better photogenerated charge carriers separation as a result of heterojunction construction between Nd2O3 and ZnO interfaces. In addition, the 3%Nd2O3/ZnO photocatalysts showed sufficient stability for five repeated runs and created its potential utility for mitigation of organic pollutants in comparison to pure ZnO and commercial P-25.

Facile one-pot solvothermal technique to synthesis ZnS / graphene nanoplatelets (0.2) nanocomposites

In this work, we report the fabrication of ZnS / graphene nanoplatelets (0.2) nanocomposites (ZnS/G(0.2)) by a simple step solvothermal manner. The nanocomposite with weight ratio (0.2) of graphene nanoplatelets was prepared and characterized by several techniques. X-Ray diffraction measurements have shown three sharp peaks at (111) ‘(220) ‘(311) Miller indices, which referred to Sphalerite and Wurtzite phases of the cubic face. The average crystal sizes of 11.03 nm to 14.41 nm for ZnS nanoparticles. The graphene nanoplatelets enhanced crystallinity properties of prepared nanocomposites. Fourier-transform infrared and Raman spectrums confirm formation of ZnS nanoparticles and ZnS/G(0.2) nanocomposites. Furthermore, FESEM was performed to study morphology and structure of nanocomposites. BET isotherm, and the BJH method have given information consistent with Type V with the H3 hysteresis loops. Moreover, the results have supported the effective change in the surface area, pore-volume, pore diameter, and external surface area values.

Recovery of nanosized silica and lignin from sugarcane bagasse waste and their engineering in fabrication of composite membrane for water purification.

Environmental benign catalytic process was developed for the valorisation of sugarcane bagasse into functional nanomaterials. Bagasse saccharification was carried out with an acid catalyst (H2SO4 0.5%, wt/wt) to separate sugars after pre-treatment of biomass with ethanol. Subsequently, a combination of peroxide and base (0.5% H2O2, wt/wt and 1% NaOH, wt/wt) was stacked to concurrently synthesise SiO2 (35nm with 5.65% yield) and lignin (20nm with 10.15% yield) from bagasse slurry. In the final step, precipitation using catalyst was completed to separate highly pure functional materials in powdered form. Zeta potential (ζ) of the synthesised materials was found to be - 35.6mV for SiO2 and - 13.1mV for lignin. Obtained silica and lignin nanomaterials were used in the fabrication of strong as well as flexible functional membrane for purification of solute particles and gases. The adsorption/desorption curve of the developed functional membrane showed type II isotherm with a H3 hysteresis loop. The observed Brunauer-Emmett-Teller surface area of the membrane was 400.3m2/g. The pore size and pore volume as recorded by Barrett-Joyner-Halenda method was 25.5nm and 0.624cm3/g, respectively. Hence, the developed simple and sustainable process could be highly suitable for filtration of contaminated water and air purification.

Novel green synthesis of hydroxyapatite uniform nanorods via microwave-hydrothermal route using licorice root extract as template

Hydroxyapatite (HAp) nanorods were synthesized in the presence of licorice root extract (LE) as a green organic template (or biotemplate) at 125 °C through a microwave-hydrothermal synthesis route. The products were characterized for shape, size, crystallinity, and phase purity. For the sample prepared in the presence of LE (denoted as HAp_L, powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) revealed a uniform hexagonal phase nanorod product with average dimensions of 105 nm length and 25 nm width. The control sample, prepared in the absence of LE (denoted as HAp_W), showed less crystallinity and poorer morphology. Thermogravimetric analyses (TGA) and differential thermal analyses (DTA) indicated minor moisture contents in both samples. Fourier transform infrared spectroscopy (FT-IR) indicated carbonate-free samples. Raman spectroscopy confirmed the phase purity of the products. Energy-dispersive X-ray spectroscopy (EDX) analysis showed that product HAp_L has a Ca/P atomic ratio close to the theoretical value of HAp. Compared to HAp_W, ζ-potential measurements have shown that suspensions of sample HAp_L were more stable in different aqueous salt solutions. Particle size distribution analysis (PSA) showed a narrow size distribution for sample HAp_L with an average particle size of 105 nm which is advantageous over the apparently multi-disperse sample HAp_W. Nitrogen adsorption/desorption isotherms for both samples showed type III trends, having H3 hysteresis loops in the P/Po range between 0.9 and 1.

Use of activated bentonite-alginate composite beads for efficient removal of toxic Cu2+ and Pb2+ ions from aquatic environment

The toxic heavy metals contamination in water bodies is one of the major concerns in many countries. Copper and lead are the two common toxic metals present in aquatic environments due to their extensive usage in various industries for diverse applications. The present study deals with the removal of these two toxic heavy metal ions using activated bentonite-alginate (ABn-AG) composite beads which are easily separated and recovered after adsorption reaction. Composite beads were prepared by adapting the ionic gelation method and the materials; i.e., raw bentonite (BnR), activated bentonite (ABn) and ABn-AG were characterized by XRD, BET surface area, TGA-DTA, FT-IR, SEM analyses. The nitrogen adsorption–desorption isotherm obtained for the materials were the type IV isotherm with characteristics H3 hysteresis loops indicating the presence of mesopores with slit-shaped pores. Batch experiments showed that reasonably high percent removal was achieved even at highly acidic conditions, i.e., 58% of Cu2+and 77% of Pb2+were removed at pH 2.0. The removal was fast during the initial contact time and the adsorption data obtained at various contact time were fit well to the pseudo-second order kinetic model. The maximum sorption capacity for Cu2+ was found to be 17.30 mg/g whereas Pb2+ was found to be 107.52 mg/g. The presence of MgCl2, NaCl and KCl did not cause significant influence on the removal of Cu2+ and Pb2+ using ABn-AG. Binary adsorption study suggested that Cu2+ and Pb2+ were removed through different binding sites present in ABn-AG. Reusability test showed that removal of Cu2+ and Pb2+ decreased by 10% only after the same material was reused for 5 times indicating that ABn-AG is a highly robust material and can be reuse for several times without losing its efficiency. Thus, this study suggested that ABn-AG composite beads can be employed as an efficient adsorbent for the removal of Cu2+ and Pb2+ from aqueous waste.