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There has been growing interest in making adsorbents more cost-effective and feasible in low resource areas by using material that is cheap or would usually be considered waste. In the present study, a high-capacity regenerable adsorbent is synthesized by the treatment of waste tire rubber (WTR) with concentrated sulfuric acid. The sulfuric acid reflux carbonized as well as functionalized the WTR with the sulfonic acid group. The as-prepared sulfonated carbonaceous WTR was used for the removal of organic dyes and antibiotic viz. methylene blue (MB), methyl orange (MO) and Tetracycline (TC) from water. The maximum adsorption capacity was found to be about 833, 588, and 303 mg/g towards MB, MO, and TC, respectively. The adsorption of MB, MO, and TC from the tap water matrix was also performed and shown to maintain similar adsorption capacities as the deionized water. In addition, a packed glass column was prepared to demonstrate the continuous adsorption of MB and TC from the tap water matrix. The regeneration of the column was achieved by using mixture of aqueous and organic solvents with dissolved NaOH and it was demonstrated that the adsorbent not only recovered but also increased its adsorption capacity after every time it was regenerated. [ABSTRACT FROM AUTHOR]

We demonstrate sodium rhodizonate as a novel dual-functional reducing and stabilizing agent to form gold nanoparticles (AuNPs) of controlled size based on temperature. At room temperature (ca. 23 °C), the method generates AuNPs with an average size of ∼11 nm, whereas at 80 °C, it forms AuNPs with an average size of ∼7 nm. The rhodizonate-stabilized AuNPs readily bind to cellulose fibers (CF) while maintaining a high catalytic activity. The catalytic activity of the CF-supported AuNPs nanocomposites is demonstrated by the reduction of 4-nitrophenol (4-NP) and organic dyes such as methyl orange (MO), methylene blue (MB) in water. A glass column-based continuous catalytic reduction and its recyclability is also demonstrated for practical applications. [ABSTRACT FROM AUTHOR]

In this study, the preparation of sulfonated resorcinol-formaldehyde (RF-SO 3 H) microspheres having high adsorption capacity towards organic dyes is reported. The ability for facile regeneration of the RF-SO 3 H microspheres is also demonstrated, which may allow for the re-use of the adsorbent as well the re-utilization of the dyes. The RF-SO 3 H microspheres exhibited high adsorption capacity towards the anionic and cationic organic dyes such as methyl orange (MO) and methylene blue (MB) from the water. The equilibrium adsorption capacity was measured to be 710 mg/g and 511 mg/g towards MO, and MB, respectively. The effect of pH, contact time, and initial concentration of dyes was analyzed and shown that the adsorption capacity for MO increases in acidic pH and vice versa for MB. The adsorption of MO and MB from tap water was also performed and shown to maintain similar adsorption capacity as in the deionized water. In addition, a packed glass column was prepared to demonstrate the continuous adsorption of MO and MB under flow conditions. Regeneration of the column was achieved by using organic solvents and it was demonstrated that the adsorbent not only recovered but also increased its adsorption capacity after every time it was regenerated. [ABSTRACT FROM AUTHOR]

The current study deals with the synthesis and development of nickel and copper-based nanocatalysts for NaBH4-mediated reduction of environmental pollutants. To achieve this, metallic Ni and Cu nanoparticles-embedded carbon sheets, namely as C@Ni and C@Cu, are synthesized through annealing of Ni-BDC and Cu-BDC metal-organic frameworks (MOFs) under an argon atmosphere at 600 °C. XRD analysis showed that the Cu-BDC and Ni-BDC MOFs convert completely to the corresponding C@Ni and C@Cu nanocatalysts upon annealing. SEM and TEM micrographs illustrated decoration of nanoscale metallic Ni and Cu nanoparticles over porous carbon sheets. Raman analysis of the C@Ni and C@Cu nanocatalysts illustrated the existence of carbon as graphite with D and G bands. Vibrating Sample Magnetometer (VSM) measurements also revealed the superparamagnetic behavior of the C@Ni nanocatalyst. Their catalytic performance was tested for the catalytic reduction of environmental pollutants such as 4-nitrophenol, methyl orange and methylene blue. The obtained results from the catalytic studies are comparable with previously reported many other noble metal-based and transition metal-based nanocatalysts. Moreover, the catalytic performance of the developed catalysts dropped slightly (<3–6%) upon five times of recycling and reusing, showing the highly stable nature of the developed magnetic C@Ni and C@Cu nanocatalysts. Unlabelled Image • C@Ni and C@Cu nanocatalyst were prepared by a green method from MOF precursors. • C@Ni and C@Cu nanocatalyst could catalyze 4-NP, MO and MB solution in just 1 min. • VSM analysis confirmed the superparamagnetic behavior of C@Ni nanocatalyst. • They can be reused up to 5 cycles with minimal loss in reduction performance. • The prepared C@Ni catalyst is magnetically separable and very stable. [ABSTRACT FROM AUTHOR]

Herein, magnetic C@Fe nanocatalyst was prepared via the direct carbonization of Fe-BDC (benzene-1,4-dicarboxylic acid) metal organic framework and utilized for the catalytic reduction of 4-nitrophenol (4-NP) and methyl orange (MO). The nanocatalyst was characterized using VSM, TEM, SEM, EDS, FTIR, XRD and TGA instruments. The nanocatalyst showed excellent catalytic performance and good reusability. The calculated apparent rate constant was 1.34 min−1 and 0.92 min−1 for the 4-NP and MO reduction, which is higher than that of numerous previously reported nanocatalysts. Consequently, magnetically recoverable C@Fe nanocatalyst could be considered as a promising nanocatalyst due to their easy preparation and excellent activity. Unlabelled Image • C@Fe nanocatalyst was prepared by direct carbonization of Fe-BDC MOF. • Carbonization temperature plays a vital role for the phase transition. • VSM measurements confirmed the ferromagnetic behavior of C@Fe nanocatalyst. • C@Fe-800 can catalyze 4-NP and MO reduction reaction in 4 min. • The prepared catalyst is very stable and magnetically separable. [ABSTRACT FROM AUTHOR]

Herein we report a simple, facile and green technique for the preparation of magnetic cobalt nanoparticles (NPs) embedded on porous carbon (C@Co) nanocatalyst using MOFs template and explored for the catalytic reduction of Methyl orange (MO) and 4-Nitrophenol (4-NP). The morphology, structure and composition of the nanocatalyst were characterized by using Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), Transmission Electron Microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, thermogravimetric analysis (TGA) and Vibrating Sample Magnetometer (VSM) techniques. XRD analysis confirmed the presence of metallic Co NPs as well as their high crystalline structure. TEM analysis revealed that all the Co NPs are wrapped and protected by the porous carbon matrix. Catalytic studies revealed that the prepared magnetic C@Co nanocatalyst could catalyze the reduction of MO and 4-NP in 2 min effectively. Furthermore, the nanocatalyst showed an outstanding reusability and recyclability characteristics that remained unchanged even after several cycles. Consequently, this research offers a highly active, recyclable and magnetically isolable nanocatalyst, which can be utilized for many catalytic industrial processes. In this regard, the magnetic C@Co nanocatalyst could be a potential candidate for the wastewater treatment. Unlabelled Image • C@Co nanocatalyst was synthesized by direct carbonization of Co-BDC MOF precursors. • Co NPs are protected and wrapped by porous carbon matrix confirmed by TEM. • C@Co nanocatalyst is highly ferromagnetic in nature confirmed by VSM. • C@Co is highly active and can catalyze MO and 4-NP reduction reaction in 2 min. • The nanocatalyst is very stable and can be separated by using external magnet. [ABSTRACT FROM AUTHOR]