In this study, biochar derived from spent coffee grounds (SCGB) was used to adsorb norfloxacin (NOR) in water. The biochar properties were interpreted by analysis of the specific surface area, ...morphology, structure, thermal stability, and functional groups. The impacts of pH, NOR, and ion's present on SCGB performance were examined. The NOR adsorption mode of SCGB is best suited to the Langmuir model (R2 = 0.974) with maximum absorption capacity (69.8 mg g−1). By using a Response Surface Method (RSM), optimal adsorption was also found at pH of 6.26, NOR of 24.69 mg L−1, and SCGB of 1.32 g L−1. Compared with biochars derived from agriculture such as corn stalks, willow branches, potato stem, reed stalks, cauliflower roots, wheat straw, the NOR adsorption capacity of SCGB was 2–30 times higher, but less than 3–4 times for biochars made from Salix mongolica, luffa sponge and polydopamine microspheres. These findings reveal that spent coffee grounds biochar could effectively remove NOR from aqueous solutions. Approaching biochar derived from coffee grounds would be a promising eco-friendly solution because it utilizes solid waste, saves costs, and creates adsorbents to deal with emerging pollutants like antibiotics.
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•Norfloxacin was removed using biochar derived from spent coffee grounds (SCGB).•pH significantly influenced the Norfloxacin (NOR) adsorption of the SCGB.•Based on Langmuir model, the maximum absorption capacity was 69.8 mg g−1 at pH 6.•The adsorption process was optimized by using the response surface methodology.•Optimal adsorption conditions were achieved at pH of 6.26 and SCGB of 1.32 g L−1.
In the presence of catalytic amounts of elemental sulfur, dibenzyl disulfide/DMSO was found to be an excellent thiobenzoylating agent of amines to provide a wide range of thioamides. The reaction ...becomes autocatalytic when anilines substituted by an o‐cyclizable group were used as nucleophile, leading to the corresponding 2‐aryl aza heterocycles.
Malonic acid derivatives could be conveniently prepared with high degree of functional flexibility via redox condensation reactions between anhydride maleic, amines, elemental sulfur and DMSO as ...oxidant. This multicomponent decarboxylative transformation consists in a cascade of ring opening, decarboxylative oxidative thioamidation at temperature as low as 50 °C.
In this work, we proposed a facile approach to fabricate a superhydrophobic surface for anti-icing performance in terms of adhesive strength and freezing time. A hierarchical structure was generated ...on as-received Al plates using a wet etching method and followed with a low energy chemical compound coating. Surfaces after treatment exhibited the great water repellent properties with a high contact angle and extremely low sliding angle. An anti-icing investigation was carried out by using a custom-built apparatus and demonstrated the expected low adhesion and freezing time for icephobic applications. In addition, we proposed a model for calculating the freezing time. The experimented results were compared with theoretical calculation and demonstrated the good agreement, illustrating the importance of theoretical contribution in design icephobic surfaces. Therefore, this study provides a guideline for the understanding of icing phenomena and designing of icephobic surfaces.
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•Ternary NiCo/Mn/GO catalyst was rationally sysnthesized.•NiCo/Mn/GO exhibited excellent electron transport capability and PMS activation.•CIP degradation by NiCo/Mn/GO + PMS system ...occurred over different water conditions.•Radicals and non-radicals were involved in CIP degradation by NiCo/Mn/GO + PMS.•NiCo/Mn/GO was sustainable in multiple cycles of CIP degradation efficiency.
A catalyst, NiCo2O4/MnOOH/GO, was successfully synthesized by immobilizing NiCo2O4 and graphene oxide (GO) on MnOOH for the activation of peroxymonosulfate (PMS) with enhanced catalytic activity in ciprofloxacin (CIP) degradation. Results demonstrated 99% removal of CIP (0.02 mM) in the NiCo/Mn/GO system after 30 min at 0.2 mM of PMS and 0.15 g/L of NiCo/Mn/GO. The effects of solution pH, catalyst dose, PMS concentration, major inorganic ions, and natural organic matter (NOM) on CIP degradation were studied. The NiCo/Mn/GO exhibited good sustainability in catalytic removal efficiency for multiple uses. Furthermore, scavenger tests and electron paramagnetic resonance (EPR) results showed that singlet oxygen (1O2), superoxide radicals (O2•-), sulfate radicals (SO4•−), and hydroxyl radicals (•OH) were generated in the NiCo/Mn/GO + PMS system and participated in CIP degradation. The NiCo/Mn/GO is a promising catalyst for PMS activation in the degradation of CIP and other emerging contaminants.
A wide variety of functionalized 2-aryl benzimidazoles can be prepared by a solvent-free cobalt- or iron-catalyzed redox condensation of 2-nitroanilines and benzylamines. The cascade including ...benzylamine oxidation, nitro reduction, condensation, and aromatization occurs without any added reducing or oxidizing agent. The method can be extended to other alkylamines as reducing components or 2-nitrobenzamides as oxidizing components when using an iron/sulfur catalyst to afford various diazaheterocycles.
A straightforward access to 2‐amino‐3‐arylthiophenes has been developed via one‐pot two‐step three‐component reaction of arylacetonitriles, chalcones and elemental sulfur. The first step consists of ...a DBU‐catalyzed formation of Michael adduct between arylacetonitriles and chalcones. The second step is a cascade of DABCO‐catalyzed sulfuration of the Michael adduct with elemental sulfur followed by an oxidative cyclization to afford thiophenes. Compared to the Gewald reactions and related transformations which are limited in acetonitriles bearing a methylene group activated by an α‐substituted electron withdrawing group as substrates, our method can be applied to a wide range of arylacetonitriles and requires only catalytic amounts of DBU and DABCO. The developed reaction opens an access to 3‐aryl‐2‐aminothiophenes complementary to classical Gewald reactions with high degree of structural diversity and atom efficiency.
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•Gas sensing properties of two types of Ni based metal-organic frameworks were examined.•Better gas sensing performance was related to the smaller pore size, higher surface area, and ...higher concentration of Ni2+ sites.•Selective detection of CO was achieved by the special interaction between open Ni sites and CO gas molecules.
In this study, two different kinds of MOFs such as Ni-VNU-74-I and -II were examined for CO gas sensing. The Ni-VNU-74-I and -II showed different pore sizes and surface areas. The as-synthesized iso-reticular type Ni-VNU-74-I and -II sensors showed well crystallin chrysanthemums like morphology with great thermal stability, and surface areas (up to 2350 m2/g). Gas-sensing studies were performed systematically at different temperatures and towards different gases. The Ni-VNU-74-II gas sensor showed a stronger gas response (Ra/Rg = 1.7) to 50 ppm CO gas than to other gases at 200 °C because of the higher quadrupole moment of the CO gas molecules, leading to a strong interaction with a partial charge in the open metal Ni sites. In addition, the better performance of the Ni-VNU-74-II gas sensor compared to the Ni-VNU-74-I gas sensor (Ra/Rg for 50 ppm CO gas = 1.2) was related to the better interaction between the open metal sites (Ni) and CO molecules through a special structure of the Ni-VNU-74-II gas sensor with smaller pore sizes, higher surface area, and higher concentration of open metal Ni2+ sites. The sensing performance in this work indicates Ni-MOFs as the potential gas sensors for the detection of harmful gases in practical applications.
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