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Two-dimensional MXene with layered structure has recently emerged as a nanomaterial with fascinating characteristics and applicability. Herein, we prepared the newly modified magnetic MXene (MX/Fe3O4) nanocomposite using solvothermal approach and investigated its adsorption behavior to study the removal efficiency of Hg(II) ions from aqueous solution. The effect of adsorption parameters such as adsorbent dose, time, concentration, and pH were optimized using response surface methodology (RSM). The experimental data fitted well with quadratic model to predict the optimum conditions for maximum Hg(II) ion removal efficiency which were found to be at adsorbent dose 0.871 g/L, time 103.6 min, concentration 40.17 mg/L, and 6.5 pH respectively. To determine the adequacy of the developed model, a statistical analysis of variance (ANOVA) was used, which demonstrated high agreement between the experimental data and the suggested model. According to isotherm result, the experimental data were following the best agreement with the Redlich-Peterson isotherm model. The results of the experiments revealed that the maximum Langmuir adsorption capacity of 699.3 mg/g was obtained at optimum conditions, which was closed to the experimental adsorption capacity of 703.57 mg/g. The adsorption phenomena was well represented by the pseudo-second-order model (R2 = 0.9983). On the whole, it was clear that MX/Fe3O4 has lot of potential as a Hg(II) ion impurity removal agent in aqueous solutions. [ABSTRACT FROM AUTHOR]

Water‐dispersible and fluorescence‐stable carbon quantum dots (CQDs) have been synthesized at gram scale using pyrene as carbon precursor by employing the bottom‐up approach. X‐ray diffraction, FTIR, Raman spectroscopy and UV visible spectroscopy confirm the formation of CQDs. TEM images shows that size of the CQDs ranges from 2 to 5 nm. A detailed study of their optical and fluorescence characteristics was performed. Their aqueous dispersion radiates bright yellow light under UV lamp (365 nm). The research work includes derivation of their excitation wavelength, observation of influence of dilution on fluorescence and monitoring of emission intensity for about 4 months. The CQDs can effectively recognize the presence of heavy metal ions in aqueous medium at neutral pH via fluorescence quenching. [ABSTRACT FROM AUTHOR]

High‐level pseudocapacitive materials require incorporations of significant redox regions into conductive and penetrable skeletons to enable the creation of devices capable of delivering high power for extended periods. Coordination nanosheets (CNs) are appealing materials for their high natural electrical conductivities, huge explicit surface regions, and semi‐one‐layered adjusted pore clusters. Thus, rational design of ligands and topological networks with desired electronic structure is required for the advancement in this field. Herein, we report three novel conjugated CNs (RV‐10‐M, M=Zn, Ni, and Co), by utilizing the full conjugation of the terpyridine‐attached flexible tetraphenylethylene (TPE) units as the molecular rotors at the center. We prepare binder‐free transparent nanosheets supported on Ni‐foam with outstanding pseudocapacitive properties via a hydrothermal route followed by facile exfoliation. Among three CNs, the high surface area of RV‐10‐Co facilitates fast transport of ions and electrons and could achieve a high specific capacity of 670.8 C/g (1677 F/g) at 1 A/g current density. Besides, the corresponding flexible RV‐10‐Co possesses a maximum energy density of 37.26 Wh kg−1 at a power density of 171 W kg−1 and 70 % capacitance retention even after 1000 cycles. [ABSTRACT FROM AUTHOR]

An approach towards the synthesis of aluminum modified graphene oxide (GO) has been studied in the present manuscript. Graphene oxide has been modified by the aluminum sulfate followed by alkalization to synthesized Al-GO composite. GO and Al-GO composite has been characterization by the means of different techniques i.e. XRD, FT-IR, FT-Raman, TEM, SEM, TGA and elemental mapping. Analysis confirmed the formation of GO and Al-GO composite. The prepared GO composite has been checked for the removal of fluoride from the potable water with different initial concentration of fluoride ions. Composite shows it's effectiveness for the removal of fluoride throughout the pH range. The maximum adsorption capacity and Langmuir constant determined for the adsorbent dose of 1 g L−1 are found to be 38.31 mg g−1 and 0.5252 L mg−1 respectively.GRAPHICAL ABSTRACT [ABSTRACT FROM AUTHOR]

Graphene quantum dots (GQDs) have been prepared from graphene oxide (GO) and characterized by standard analytical techniques. The size of the prepared GQDs ranges from 2-10 nm. Aqueous dispersion of GQDs exhibited excitation-dependent emission behavior. Emission intensity of the aqueous dispersion found stable for the examined duration of about four months. GQDs exhibited selective recognition of Fe3+ and Cr3+ out of various common ions such as alkali, alkaline-earth and transition metal ions in aqueous medium through fluorescence quenching. The lower limit of detection of Fe3+ is 1 μM and that of Cr3+ is 4 μM. [ABSTRACT FROM AUTHOR]

The advancement in membrane-based separation technologies offers advantages over traditional ways. Recovery of acid from acidic waste stream is an important issue to be solved by greener route. Diffusion dialysis using anion exchange membranes (AEMs) is an energy-intensive and environment friendly process to be taken forward. Herein, we report the eco-friendly route for chloromethylation of polysulfone using chloromethyl ethyl ether (CMEE). Effect of chloromethyl ethyl ether concentration, reaction temperature, and reaction time are investigated to get maximum tethered chloromethyl group and high yield of product. Series of chloromethylated polysulfone membranes are prepared with different concentrations of graphene quantum dots (GQDs) followed by quaternization using trimethylamine. The prepared membranes are characterized by their water content, transport properties, and stabilities. Composite membranes show enhanced water uptake, ion exchange capacity, and mechanical stability compared to that of pristine membrane. Interestingly, to address the environmental impact of acids present in industrial waste, AEMs are employed for acid recovery from model waste at higher concentrations of acid and salt using diffusion dialysis. For prepared membranes, 35.5–47.5% acid recovery has been achieved in presence of metal ions. SCE-1.0 (1.0 wt % GQD/ QPSU) membrane shows the highest acid recovery (47.5%) among the membranes. Composite membranes suggest their potential utility in acidic effluent treatment via diffusion dialysis. Image 1 • Polysulfone/GQD composite AEMs have been synthesized successfully. • Composite membranes show good ionic conductivity with stability. • AEMs showed its application in acid recovery by diffusion dialysis. [ABSTRACT FROM AUTHOR]