Water lubrication of graphene oxide-based materials

Water is as an economic, eco-friendly, and efficient lubricant that has gained widespread attention for manufacturing. Using graphene oxide (GO)-based materials can improve the lubricant efficacy of water lubrication due to their outstanding mechanical properties, water dispersibility, and broad application scenarios. In this review, we offer a brief introduction about the background of water lubrication and GO. Subsequently, the synthesis, structure, and lubrication theory of GO are analyzed. Particular attention is focused on the relationship between pH, concentration, and lubrication efficacy when discussing the tribology behaviors of pristine GO. By compounding or reacting GO with various modifiers, amounts of GO-composites are synthesized and applied as lubricant additives or into frictional pairs for different usage scenarios. These various strategies of GO-composite generate interesting effects on the tribology behaviors. Several application cases of GO-based materials are described in water lubrication, including metal processing and bio-lubrication. The advantages and drawbacks of GO-composites are then discussed. The development of GO-based materials for water lubrication is described including some challenges.

Photocatalytic Degradation of Malachite Green using Undoped and Carbon-Doped Calcium Molybdate Catalysts

Calcium molybdates (undoped and carbon-doped) have been used as a photocatalyst for the degradation of malachite green. These have been characterized by different techniques such as FE-SEM, EDX and XRD. The progress of the reaction has been monitored spectrophotometrically. Different rate affecting parameters like pH, concentration of dye, amount of semiconductor and light intensity have been studied and their optimum values obtained are pH 9.7, concentration of malachite green as 5.00 × 10-4 M, 0.12 g of CaMoO4 and light intensity as 50.0 mWcm–2. A tentative mechanism for the photocatalytic degradation of dye has been proposed, where hydroxyl radical has been observed as an active oxidizing species.

Synthesis, Identification, and Infrared Spectroscopy Study of the Influence of Reaction Parameters Variations on Cu(C4O4).2H2O Synthesis

In this paper, we report synthesis, identification and study of different spectral measurements for Cu(C4O4).2H2O complex, in order to valorize effect of experimental conditions on resulting product nature. The structure was identified from a powder X rays diffraction. This complex was prepared for the first by Christian Rubel and Armin Weiss (1986). Comparative study for variation of different reaction parameters effect was interpreted by infrared spectrum observation for each product. In conclusion, we have put in evidence contribution effect of variation in temperature, pH, concentration, solvent, time of reaction on nature modification of the resulting product

SPECTROSCOPIC EVALUATION OF ACTIVATED CHARCOAL AS A POISON ANTIDOTE FOR GLICLAZIDE DRUG

Objective: The aim of the present study is to evaluate the ability of activated charcoal in adsorbing overdosage of gliclazide drug, and to study the effects of pH, concentration and time on this process.Methods: To evaluate the effect of pH, concentration and time; 50 ml of the drug solution (100 mg/L) were allowed to stand with the activated charcoal for 1 h at pH of 1.5, 4, 7, and 9 for pH study. 50 ml of the drug solution concentrations of 25, 50, 75, and 100 (mg/L) were allowed to stand with 1 g activated charcoal for 1 h for concentration study. 50 mg of the drug solution (100 mg/L) were allowed to stand with the activated charcoal for 15, 30, 45, and 60 min for time study. The concentrations of the adsorbed drug were determined spectrophotometrically.Results: The adsorption of the gliclazide drug on activated charcoal was found to be pH, concentration, and time-dependent. The amounts of the drug adsorbed were 3, 0.75, 0.6, and 0.5 mg/g for pHs 1.5, 4, 7, and 9, respectively, for pH study. For concentration study, the amounts adsorbed were 0.15, 0.22, 0.33, and 0.58 mg/g for concentrations 25, 50, 75, and 100 mg/L, respectively. For time study, the amounts were 0.3, 0.4, 0.51, and 0.65 mg/g for reaction times 15, 30, 45, and 60 min, respectively.Conclusion: The best adsorption circumstances of gliclazide drug on activated charcoal that were found; acidic pH, a high concentration of the drug and longtime of contact.