Graphene Oxide Content Research Articles

Effect of Graphene Oxide on compressive strength of Shale Ceramsite high strength lightweight aggregate concrete

The use of shale ceramsite to produce high-strength lightweight concrete (HSLWC) in the construction industry is an effective method for sustainable development and environmental protection. The growing demand for HSLWC has stimulated the development of nanomaterials to further enhance mechanical properties. This study investigated the effect of graphene oxide (GO) on the properties of HSLWC with shale ceramsite as a coarse and fine aggregate, including workability, density, compressive strength, and energy dispersive spectrometer (EDS) test. The control mixture was designed according to the standard of grade 40 high strength concrete, and four groups of mixtures were prepared by adding doses of GO at 0.00%, 0.02%, 0.04% and 0.06% by weight of cement to the control mixture. The experimental results showed that HSLWC with the 28-day compressive in the range of 43-54 MPa and the oven dry density of 1705-1783 kg/m3 could be produced by using shale ceramsite and shale pottery sand as coarse aggregate and fine aggregate, respectively. Simultaneously, adding a low content of GO to HSLWC could slightly increase the density, rationally reduce the slump, and significantly enhance the compressive strength. The EDS results showed that the reason for the increase in compressive strength was that GO could accelerate the cement hydration process and regulate the crystal morphology of the cement.

Investigation on baicalin‐loaded chitosan film crosslinked by graphene oxide and its biocompatibility

AbstractChitosan has good biocompatibility, in vivo biodegradability and certain physiological activity, which can be used as a drug carrier to stabilise and protect drug components, causing the promotion of drug absorption and controlling drug release. Using graphene oxide (GO) as a cross‐linking agent, the functional groups in its lamellar structure can interact effectively with the functional groups in chitosan molecules, leading to enhanced mechanical properties and optimize the controlled drug‐release behaviour. GO/chitosan composite films were prepared by the solution mixing method with various GO content and exhibit many hydrogen bonds between the GO and chitosan. There were no obviously agglomerated GO particles in the surface of composite films, and the lamellar structure can be observed in the cross section of the composite films. Differential thermal analysis (DTA) indicated that the addition of GO increased the stability of the chitosan film. The baicalin‐loaded GO/Chitosan also exhibited pH dependent release behaviour, with an increasing release amount and rate at lower pH medium. In addition, the result of biological evaluations showed that the GO/Chitosan films had good cytocompatibility in vitro and histocompatibility at appropriate GO concentrations. This investigation offered a new pH‐dependent drug carrier potentially applied for tumour and atherosclerosis treatment.

Impact of graphene oxide addition on pharmaceuticals removal in anaerobic membrane bioreactor

The addition of conductive materials to the anaerobic digestion bioreactor was suggested to enhance microbial activity. In the present work, an anaerobic membrane bioreactor treating municipal wastewater was operated for 385 days. The impact of different graphene oxide concentrations on the removal target pharmaceuticals and microbial community dynamics was investigated. The addition of graphene oxide did not impact the reactor stability, whereas the removals of antibiotics (e.g., trimethoprim and metronidazole) were enhanced. A shift in the microbial community was detected after the addition of 50–900 mg L−1 of graphene oxide, with the proliferation hydrogenotrophic methanogens. The proliferation of syntrophic microorganisms may indicate interactions via direct interspecific electron transfer. The obtained results suggest that the addition of graphene oxide at low mg L−1 concentrations to an anaerobic membrane bioreactor may be considered to improve the removal of antibiotics from municipal wastewater.

Development of Graphene Oxide/Polyethylene to enhance mechanical properties through melt mixing technique

Graphene Oxide (GO) was added to Low-Density Polyethylene (LDPE) to test the mechanical properties of the compound. Compared to other types of polyethylene, LDPE provides a good balance of mechanical properties and processability, which leads to its being chosen as the research’s matrix material. This experiment aims to prepare LDPE/GO through melt mixing technique and analyse mechanical properties of tensile strength/tensile elongation of LDPE/GO composite based on GO concentration (0, 0.5, 1.0 and 1.5 wt%). The compounding of LDPE/GO was blended using a five-stage twin-screw extruder under specific conditions before going through the moulding process at melting temperature. The composites were cut according to ASTM D638 specimen dimension. The tensile properties of LDPE composites were filled separately with different weight fractions of GO at a 50 mm/min rate. It was found that the values of Young’s modulus of the composites increased, but the values of the tensile elongation at break decreased with increasing the GO weight fraction. The relatively big interfacial area and excellent interfacial adhesion between the matrix and the GO may be responsible for the composites’ reinforcement. This study provided a basis for further development of GO-reinforced LDPE composites with desirable mechanical performance and good damage behaviour.

Preparation of antibacterial PHBV/GO nanocomposite membranes via electrospinning

Poly(3-hydroxybutyrate-co-3-hydroxypentanoate) (PHBV)/graphene oxide (GO) composite membranes were electrospun with an aim at fabricating antibacterial nanofibrous scaffolds for tissue engineering application. Randomly and aligned oriented PHBV/GO fibrous membrane were prepared by controlling the mixed solvent, GO concentration and process parameters, and their effect on the morphology and structure of the membranes was investigated. When 10 wt% GO nanosheets was incorporated into the composite spinning dope, PHBV/GO membrane presented a 18.7 MPa breaking strength and 5.51 × 102 MPa tensile modulus, much greater than 14.3 MPa and 1.76 × 102 MPa of PHBV membrane. Colonies forming units of E.coli and S.aureus reduced by 81.7% and 71.8% for randomly oriented PHBV/GO, and 84.2% and 73.4% for aligned oriented PHBV/GO when compared to PHBV membrane. The development of bacterial biofilm on PHBV/GO membrane reduced greatly when incorporating 5–10 wt% GO. The antibacterial PHBV/GO membranes with better mechanical properties showed great promise for further studies on bone tissue repair.

"The influence of graphene oxide on the photocatalytic activity of nanocomposite material"

"In this paper, is investigated the photocatalytic activity of a nanocomposite material based on titanium and graphene oxides. The sample was obtained by hydrothermal synthesis. The photoactalytic activity of nanocomposites was studied by the transient responce of the photoinduced current. Charge transfer resistances were also investigated using electrochemical impedance spectroscopy. Identification of nanocomposite materials was carried out using Raman and FTIR spectroscopy. This combination shows that there is a connection between the original components. Raman spectroscopy shows that the peaks obtained are characteristic of both titanium dioxide and graphene oxide. At the same time, the ID/IG ratio shows the reduction of graphene oxide during hydrothermal synthesis. And FTIR spectroscopy shows that there is a Ti-O-C bond below the 1000 cm-1 mode. The absorption ability also affects the increase in the photocurrent of the nanocomposite material. Absorption spectra show a shift to the long-wavelength region of light due to the transparency of graphene oxide in the visible region. The concentration of graphene oxide plays an important role in increasing the efficiency of the nanocomposite material. In this work, the concentration of the graphene oxide is equal to 7 wt% with respect to titanium dioxide. Keywords: nanocomposite material, titanium dioxide, graphene oxide, hydrothermal synthesis, photocatalytic activity."

Tailoring the Electron Trapping Effect of a Biocompatible Triboelectric Hydrogel by Graphene Oxide Incorporation towards Self-Powered Medical Electronics.

Triboelectric nanogenerators (TENGs) are associated with several drawbacks that limit their application in the biomedical field, including toxicity, thrombogenicity, and poor performance in the presence of fluids. By proposing the use of a hemo/biocompatible hydrogel, poly(2-hydroxyethyl methacrylate) (pHEMA), this study bypasses these barriers. In contact-separation mode, using polytetrafluoroethylene (PTFE) as a reference, pHEMA generates an output of 100.0 V, under an open circuit, 4.7 μA, and 0.68 W/m2 for an internal resistance of 10 MΩ. Our findings unveil that graphene oxide (GO) can be used to tune pHEMA's triboelectric properties in a concentration-dependent manner. At the lowest measured concentration (0.2% GO), the generated outputs increase to 194.5 V, 5.3 μA, and 1.28 W/m2 due to the observed increase in pHEMA's surface roughness, which expands the contact area. Triboelectric performance starts to decrease as GO concentration increases, plateauing at 11% volumetric, where the output is 51 V, 1.76 μA, and 0.17 W/m2 less than pHEMA's. Increases in internal resistance, from 14 ΩM to greater than 470 ΩM, ζ-potential, from -7.3 to -0.4 mV, and open-circuit characteristic charge decay periods, from 90 to 120 ms, are all observed in conjunction with this phenomenon, which points to GO function as an electron trapping site in pHEMA's matrix. All of the composites can charge a 10 μF capacitor in 200 s, producing a voltage between 0.25 and 3.5 V and allowing the operation of at least 20 LEDs. The triboelectric output was largely steady throughout the 3.33 h durability test. Voltage decreases by 38% due to contact-separation frequency, whereas current increases by 77%. In terms of pressure, it appears to have little effect on voltage but boosts current output by 42%. Finally, pHEMA and pHEMA/GO extracts were cytocompatible toward fibroblasts. According to these results, pHEMA has a significant potential to function as a biomaterial to create bio/hemocompatible TENGs and GO to precisely control its triboelectric outputs.

Preparation, Characterization and Tribological Performance of Polyurethane (PU) Coatings Filled with Graphene Oxide (GO)

The polyurethane coatings containing different concentration of graphene oxide were prepared. Their physicochemical properties were characterized by XRD and SEM. The tribological behaviors were also investigated by ring-on-block tests. Results revealed that the TDI adsorb on the surface of GO through reaction with O-H. The COF were extremely sensitive to the GO concentration of PU coatings filled. The COF of pure PU coating was 0.185, whereas it is sharply decreased when 1.0 wt% GO was added. Smaller COF was obtained as the GO concentration increase and to minimize when GO concentration is 2.0 wt%. Friction reduced mechanism of GO was further investigated. Two reasons were responsible for this phenomenon. The one was that the GO itself possessed the capacity of anti-wear and friction reduction. Another one was the GO dispersed in the PU coatings could increase the strength of the coatings by the mean, which was similar to dispersion strengthening.

Graphene oxide assisted solvent for enhancing the coupled ultrasonic extraction process of curcumin from Curcuma longa L

ABSTRACT A coupled ultrasonic extraction process of curcumin from Curcuma longa L enhanced by the graphene-oxide-assisted solvent was developed. The yield was investigated in relation to extraction temperature, extraction time, ethanol volume fraction, and graphene oxide concentration. Response surface methodology was used to develop a quadratic model of the yield and extraction process. The optimum extraction parameters with the highest yield were obtained and the economic value was then assessed. Results showed that the coupling process could reduce the extraction time, extraction temperature, and ethanol volume fraction while improving the extraction yield. The optimal process parameters were 50.0°C extraction temperature, 1.5 h extraction time, 60.0% ethanol volume fraction, and 1.0 mg/g graphene oxide concentration. The highest extraction yield was 64.9 mg/g, which was better than that have been reported. It can save an estimated $1507 in production expenses for every ton of turmeric under the optimal extraction process. Moreover, the reduction in extraction temperature and ethanol volume fraction also means a safer and cleaner production environment, which highlights the greater potential application prospect of the extraction process developed in this paper.

GO nanoparticles mitigate the negative effects of salt and alkalinity stress by enhancing gas exchange and photosynthetic efficiency of strawberry plants

Considering the potential use of nanomaterials, particularly carbon-based nanostructures, in agriculture, we conducted a study to investigate the effect of graphene oxide (GO) on strawberry plants under salinity and alkalinity stress conditions. We used GO concentrations of 0, 2.5, 5, 10, and 50 mg/L, and applied stress treatments at three levels: without stress, salinity (80 mM NaCl), and alkalinity (40 mM NaHCO3). Our results indicate that both salinity and alkalinity stress negatively impacted the gas exchange parameters of the strawberry plants. However, the application of GO significantly improved these parameters. Specifically, GO increased PI, Fv, Fm, and RE0/RC parameters, as well as chlorophyll and carotenoid contents in the plants. Moreover, the use of GO significantly increased the early yield and dry weight of leaves and roots. Therefore, it can be concluded that the application of GO can enhance the photosynthetic performance of strawberry plants, and improve their resistance to stress conditions.

SnS-rGO heterojunction: Fabrication, characterization, and visible light-induced optoelectronic performance analysis

In this article, the orthorhombic phase of pristine SnS and SnS-rGO nanostructures with different concentrations of graphene oxide was synthesized by the co-precipitation method. The cracking of FESEM images in SnS-25rGO nanostructures shows the substitution of sulfur with the oxygen of the functional groups of graphene oxide. Also, the effect of the concentration of graphene oxide was investigated on the optoelectronic efficiency of fabricated devices. The optoelectronic characterization shows that by adding graphene oxide and increasing its concentration, the semi-circle radius in the EIS analysis and the amount of photocurrent decreased and increased, respectively. These results indicate the fast transport and transfer of electrons to the substrates and the effective separation of electron-hole pairs. Finally, the calculations showed that by increasing the concentration of graphene oxide in the SnS-rGO nanostructures, the visible-light-induced optoelectronic parameters of photosensitivity, photoresponsivity, specific detectivity, and external quantum efficiency of these nanostructures significantly improved. These parameters were obtained for the SnS-25rGO nanostructure as 204, 59.88 mA/cm2, 5.98 × 1010 jones, and 166.85, respectively, each of which increased several times compared to the optoelectronic parameters of the pristine SnS. Therefore, this multiplicity increase makes these SnS-rGO nanostructures suitable for photodetector applications.

Investigation of Tribological Characteristics of PEO Coatings Formed on Ti6Al4V Titanium Alloy in Electrolytes with Graphene Oxide Additives.

Coatings with a thickness from ~40 to ~50 µm on Ti6Al4V titanium alloys were formed by plasma electrolytic oxidation (PEO) in a silicate-hypophosphite electrolyte with the addition of graphene oxide. The PEO treatment was carried out in the anode-cathode mode (50 Hz) at a ratio of anode and cathode currents of 1:1; their sum density was 20 A/dm2, and the treatment's duration was 30 min. The effect of the graphene oxide's concentration in the electrolyte on the thickness, roughness, hardness, surface morphology, structure, composition, and tribological characteristics of the PEO coatings was studied. Wear experiments, under dry conditions, were carried out in a ball-on-disk tribotester with an applied load of 5 N, a sliding speed of 0.1 m·s-1, and a sliding distance of 1000 m. According to the obtained results, the addition of graphene oxide (GO) into the base silicate-hypophosphite electrolyte leads to a slight decrease in the coefficient of friction (from 0.73 to 0.69) and a reduction in the wear rate by more than 1.5 times (from 8.04 to 5.2 mm3/N·m), with an increase in the GO's concentration from 0 to 0.5 kg/m3, respectively. This occurs due to the formation of a GO-containing lubricating tribolayer upon contact with the coating of the counter-body in the friction pair. Delamination of the coatings during wear occurs due to contact fatigue; with an increase in the concentration of GO in the electrolyte from 0 to 0.5 kg/m3, this process slows down by more than four times.

Experimental and DFT study of GO-decorated CaO quantum dots for catalytic dye degradation and bactericidal potential

This research lays the groundwork for preparing graphene oxide (GO)-doped CaO nanocomposites for efficient antibacterial potential and dye degradation. The study aimed to reduce the recombination rate of the electron hole (e−/h+) of CaO and improve charge transfer. This issue can be minimized by doping high-surface area GO into CaO quantum dots (QDs). Herein, the one-pot co-precipitation technique has prepared various concentrations (1, 3, and 5 wt%) of GO-doped CaO. Characterization techniques were used to investigate optical, elemental analysis, microstructural, functional, and morphological properties. The addition of GO into QDs showed excellent catalytic activity (CA) to control sample CaO against methylene blue (MB) in basic and acidic media compared to the neutral media. The synergistic effect of morphological alternation attributed to an increase in the mechanism of CA upon doping. Various concentrations of GO to QDs promised remarkable bactericidal potency against Escherichia coli.

Cation-Driven Assembly of Bilayered Vanadium Oxide and Graphene Oxide Nanoflakes to Form Two-Dimensional Heterostructure Electrodes for Li-Ion Batteries.

Lithium preintercalated bilayered vanadium oxide (LVO or δ-LixV2O5·nH2O) and graphene oxide (GO) nanoflakes were assembled using a concentrated lithium chloride solution and annealed under vacuum at 200 °C to form two-dimensional (2D) δ-LixV2O5·nH2O and reduced GO (rGO) heterostructures. We found that the Li+ ions from LiCl enhanced the oxide/carbon heterointerface formation and served as stabilizing ions to improve structural and electrochemical stability. The graphitic content of the heterostructure could be easily controlled by changing the initial GO concentration prior to assembly. We found that increasing the GO content in our heterostructure composition helped inhibit the electrochemical degradation of LVO during cycling and improved the rate capability of the heterostructure. A combination of scanning electron microscopy and X-ray diffraction was used to help confirm that a 2D heterointerface formed between LVO and GO, and the final phase composition was determined using energy-dispersive X-ray spectroscopy and thermogravimetric analysis. Scanning transmission electron microscopy and electron energy-loss spectroscopy were additionally used to examine the heterostructures at high resolution, mapping the orientations of rGO and LVO layers and locally imaging their interlayer spacings. Further, electrochemical cycling of the cation-assembled LVO/rGO heterostructures in Li-ion cells with a non-aqueous electrolyte revealed that increasing the rGO content led to improved cycling stability and rate performance, despite slightly decreased charge storage capacity. The heterostructures with 0, 10, 20, and 35 wt % rGO exhibited capacities of 237, 216, 174, and 150 mAh g-1, respectively. Moreover, the LVO/rGO-35 wt % and LVO/rGO-20 wt % heterostructures retained 75% (110 mAh g-1) and 67% (120 mAh g-1) of their initial capacities after increasing the specific current from 20 to 200 mA g-1, while the LVO/rGO-10 wt % sample retained only 48% (107 mAh g-1) of its initial capacity under the same cycling conditions. In addition, the cation-assembled LVO/rGO electrodes exhibited enhanced electrochemical stability compared to electrodes prepared through physical mixing of LVO and GO nanoflakes in the same ratios as the heterostructure electrodes, further revealing the stabilizing effect of a 2D heterointerface. The cation-driven assembly approach, explored in this work using Li+ cations, was found to induce and stabilize the formation of stacked 2D layers of rGO and exfoliated LVO. The reported assembly methodology can be applied for a variety of systems utilizing 2D materials with complementary properties for applications as electrodes in energy storage devices.

Modulation of Electrical Characteristics of Polymer–Ceramic–Graphene Hybrid Composite for Piezoelectric Energy Harvesting

The use of lead-based ceramics to enhance the piezoelectricity of poly(vinylidene fluoride) (PVDF) is the primary challenge toward nontoxic flexible piezoelectric devices. 0.67BiFeO3-0.33BaTiO3 (BF33BT) is one of the lead-free piezoceramics with high-temperature stability and comparable piezoelectric characteristics to existing lead-based piezoceramics. The work represents PVDF–BF33BT two-phase and PVDF–BF33BT–graphene oxide (GO) three-phase composites with detailed analysis of the dielectric, ferroelectric, and piezoelectric characterizations. Solvent-casting followed by the hot-pressing technique improves the electroactive β-phase of ≥60% in the composites. With BF33BT and GO loading, the dielectric constant and loss tangent increase; however, there is an abrupt rise at the threshold GO concentration of 0.08 wt %. The three-phase composite with 40 wt % BF33BT and 0.08 wt % GO records a dielectric constant of 303 and a loss tangent of 0.68. The harvester out of the same composition achieves a piezoelectric strain constant of 9 pC·N–1, an open-circuit voltage of ∼3.9 V, and a short-circuit current of 1.3 μA. The feasibility of the harvester was tested by powering a calculator by charging a 2.2 μF capacitor after rectification. The recoverable energy density also improves seven times, indicating that the PVDF–BF33BT–GO composite is preferable for piezoelectric and energy storage applications.

Fabrication of gelatin methacryloyl/graphene oxide conductive hydrogel for bone repair

The ideal bone repair materials possess a series of properties, such as injectability, good mechanical properties and bone inducibility. In the present study, gelatin methacryloyl (GelMA) and graphene oxide (GO) were selected to prepare conductive hydrogel by changing the concentration of GelMA and GO during the cross-link process. The effects of different contents of GelMA and GO to the hydrogel performance were investigated. The results showed that the mechanical properties of the hydrogel kept 16.37 ± 1.89 KPa after adding 0.1% GO, while the conductivity was improved to 1.36 ± 0.09 μS/cm. The porosity of hydrogel before and after mineralization could reach more than 90%. The mechanical properties of mineralized hydrogel was improved significantly, could reach 26.38 ± 2.29 KPa. Cell experiments indicated that the mineralized hydrogel with electrical stimulation obviously improve the alkaline phosphatase activity of the cells. GelMA/GO conductive hydrogel could be a promising candidate for bone repair and bone tissue engineering.

A competitive-adsorption chemical vapor deposition method: Diamond coated on WC-Co substrate without acid-alkali pretreatment by adding graphene oxide particles

Detrimental components existed in substrate surface are regarded as a severe barrier of growing the chemical vapor deposition (CVD) coating. In this work, a novel competitive-adsorption CVD method was proposed to deposit the diamond coating on Co-cemented tungsten carbide (WC–Co) substrate without traditional acid-alkali pretreatment. Graphene oxide (GO) particles were adopted as the adsorbent to introduce the competitive adsorption with Co element during deposition. Four different GO concentrations were conducted to evaluate the effect of GO particles on the coating. The results shown that the WC-Co substrate with GO particles and without pretreatment can be covered by the integrated microcrystalline diamond (MCD) coating (GO-MCD) that presented the similar surface morphology to the MCD coated on WC-Co substrate with acid-alkali pretreatment (P-MCD). Furthermore, Raman spectra, AFM, XPS and XRD patterns only presented a slight difference between the GO-MCD coating and the P-MCD coating. Indentation test suggested that GO particles can enhance the adhesion strength and crack resistance of diamond coating. Meanwhile, GO particles did not deteriorate the tribological property of diamond coating. Hence, our proposed method might provide a promising approach to deposit the desired coating on the given substrate even with some detrimental components.

Regulation of bimodal structure and mechanical properties of powder-thixoformed GO/ZK60 magnesium matrix composite through adjusting GO content

Although remarkable strength enhancements can be achieved in graphene oxide (GO)/ graphene nanoplatelets (GNPs) reinforced Mg matrix composites by using the available techniques, their ductility is always quite poor due to the difficultly avoided strength-ductility trade-off. To conquer this dilemma, GO/ZK60 composites with bimodal-grain structure were fabricated using powder thixoforming in this work. The results indicate that the grain size and volume fraction of coarse grains (CGs) first decrease as the GO content increases to 0.2 wt.% and then increase again as the content increases to 0.3 wt.%, while the grain size in the fine grains (FGs) almost does not change. Consequently, the strength of the composites is improved with increasing GO content and reaches the peak values at the content of 0.2 wt.%. The composite with 0.1 wt.% GO content exhibits significantly increased tensile yield strength up to 177 ± 2 MPa while maintaining a high elongation of 23.1% ± 2.5%, being equivalent to that of the ZK60 matrix alloy. The increased FGs volume fraction, together with the promoted dislocation accumulation and storage via GO and grain refinement of large-sized CGs lead to the improvement of strain hardening ability, thus rendering the composite an excellent ductility. Furthermore, the deformation of the GO/ZK60 composites occurs progressively from the FGs to the CGs, which is opposite to the status of the milled ZK60 matrix alloy. In view of the microstructure characteristics of the composites, a new complex calculation model was proposed and it could well predict the strength of the bimodal GO/ZK60 composites. This study provides a new insight into the microstructure design and fabrication technology of GO/GNPs reinforced metal-based composites with high strength and ductility.

Investigations of graphene oxides and cement on strength performance of soil

Recent studies confirm the ability of graphene oxides (GO) for the improvement of cementitious-based soil material properties. The current study aimed to explore the influence of GO and cement on the spectroscopic, thermal, structural, and strength of soil experimentally. The spectroscopic analysis studied by FTIR showed the presence of GO and cementitious contents in the soil sample by detecting the vibration modes of respective components. Thermal (TGA) analysis revealed a slight loss in weight with the increase in temperature up to 1000 °C majorly due to the presence of moisture contents. SEM equipped with an EDX technique was implemented to examine the sample of microstructure containing GO. X-ray diffraction (XRD) recorded patterns confirmed the configuration of mineralogical contents of soil modified with GO and cement. For mechanical properties, composites samples were prepared at different concentrations of GO (0.03, 0.05, 0.1 wt% of cement) and cement (5, 10, 15, 20 wt% of the soil) to evaluate compaction characteristics, unconfined compression strength (UCS) and swelling parameters. The experimental outcomes portrayed that the increment in GO content causes prompt improvement in compressive strength (nearly 10 times compared with untreated soil sample) and reduces swelling pressure of treated soil tests. UCS behavior was boosted with the GO contents in the samples. Results depicted that the GO as an alleviating agent has significant impact on the physical features of expansive soil that will be beneficial for the construction of roads, dams, and bridges.

An insight into mimic of photo-Fenton degradation of ciprofloxacin and tetracycline

A robust Zn-BTC MOF photocatalyst deposited with varying concentrations of graphene oxide was successfully prepared using an in-situ solvothermal method and named GO@ZnMC. X-ray diffractometry, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and other techniques were used to characterize the phase component, microstructure, and optical properties of the catalysts. The photocatalytic performance of the GO@ZnMC composite was tested by degrading the antibiotics ciprofloxacin (CIP) and tetracycline (TC) with the help of hydrogen peroxide (H2O2) or calcium peroxide (CaO2) under visible light irradiation. The degradation efficiency for CIP and TC is more with CaO2 compared to H2O2 by virtue of CaO2 continuously producing H2O2. The degradation rate of the GO@ZnMC3 composite is higher when compared to that of pristine GO, Zn-MOF, and other composites. The increased photocatalytic activity is attributed to the formation of heterojunction that effectively suppresses electron-hole pair recombination. Introducing H2O2 or CaO2 encourages the formation of more active reactive oxygen species (ROS), specifically OH•, as confirmed by radical scavenging experiments, showing that the degradation reaction mimics the photo-Fenton reaction. A possible photocatalytic degradation mechanism is also proposed with the help of the LC-MS analysis. The catalyst is stable and reusable until four catalytic cycles.