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Abstract In this study, crude cellulose derived from cornstalk, after bleaching, was used as raw material for the synthesis of sodium carboxymethyl cellulose (CMC) by reacting with the cellulose with NaOH and chloroacetic acid at 75 °C for 1.5 h. Effects of alkali dosage, concentration of chloroacetic acid on the physical and chemical properties of the CMC products were investigated. It was revealed that the reactants alkali reagent/chloroacetic acid/cellulose at the molar ratio of 4.6:2.8:1and 4:2.5:1, or at the molar ratio of NaOH/ClCH 2 COOH ≈1.6–1.64, resulted in CMC products of relatively high water solubility. The viscosity-average molecular weight M v of these two CMC products obtained at molar ratios of 4.0:2.5:1 and 4.6:2.8:1 is in the range of 1.94 × 10 4 –2.48 × 10 4 g mol −1 , and the average DS of the two products are 0.57 and 0.85, respectively. As the solute concentration is above 2 wt%, the viscosity of the CMC-water solution exhibits nonlinear (exponential) increasing with increasing the solute concentration (typical of non-Newton fluids).

T oilfield is the fractured-vuggy carbonate reservoir at a temperature of around 130 °C, with salinity of up to 22 × 104 mg/L. In order to solve the problem of the high water cut in the late development stage of T oilfield, we selected XN-T from 27 kinds of swelling retarding particles by testing their swelling capacity, and coated a thin film to improve its retarding swelling capacity. The mechanisms of strong water absorption and water-holding abilities of particles were analyzed by infrared spectrometry and SEM. In the core flow experiment, the plugging rate was found to be 98.42%. Finally, the injection parameters of the coated particles were optimized to maximize the water plugging and profile control ability, resulting in an optimal particle size of 0.4–0.6 mm and a mass fraction of 10%.

The ionic liquid (IL) 1-ethyl-3-methylimidazolium dicyanamide ([EMIM][DCA]) was selected as an appropriate entrainer for the extractive distillation of the methanol–ethanol-water mixture. The COSMO-RS model was applied to screen out the appropriate solvents considering selectivity and solvent capacity together. Isobaric vapor–liquid equilibrium (VLE) experiments for the two systems of methanol–water and ethanol–water with different amounts of [EMIM][DCA] added were conducted at 101.3 kPa. The experimental data showed that [EMIM][DCA] exhibits an obvious salting effect for the methanol (or ethanol)-water mixture and eliminates the azeotropic point of ethanol–water. Moreover, the predicted values by UNIFAC-Lei model coincide well with experimental data. The separation mechanism was further explained in combination with surface charge density distribution (σ-profiles), excess enthalpy (HE), and binding energy. In addition, the flow charts were designed to evaluate the improvement of energy consumption with [EMIM][DCA] as the entrainer when compared to ethylene glycol (EG). The simulation results demonstrated that [EMIM][DCA] is more energy efficient than EG.

AbstractAtmospheric water harvesting (AWH) provides a fascinating chance to facilitate a sustainable water supply, which obtains considerable attention recently. However, ignoring the energy efficiency of AWH leads to high energy consumption in current prototypes (ca. 101 to 102 MJ kg−1), misfitting with the high‐strung and complicated water‐energy nexus. In this perspective, a robust evaluation of existing AWHs is conducted and a detailed way to high‐efficiency AWH is paved. The results suggest that using cooling‐assisted adsorption will weaken the bounds of climate to sorbent selections and have the potential to improve efficiency by more than 50%. For device design, the authors deeply elucidate how to perfect heat/mass transfer to narrow the gap between lab and practices. Reducing heat loss, recovering heat and structured sorbent are the main paths to improve efficiency on the device scale, which is more significant for a large‐scale AWH. Besides efficiency, the techno‐economic evaluation reveals that developing a cost‐effective AWH is also crucial for sustainability, which can be contributed by green synthesis routes and biomass‐based sorbents. These analyses provide a uniform platform to guide the next‐generation AWH to mitigate the global water crisis.

Titania/carbon composite hollow microspheres with bimodal mesoporous shells are one-pot fabricated by hydrothermal treatment of the acidic (NH4)2TiF6aqueous solution in the presence of glucose at180∘C for 24 h and then calcined at450∘C. The as-prepared samples were characterized by XRD, SEM, TEM, HRTEM, UV-visible spectroscopy, and nitrogen adsorption-desorption isotherms. The photocatalytic activity of the as-prepared samples was evaluated by daylight-induced photocatalytic decolorization of methyl orange aqueous solution at ambient temperature. The effects of calcination time on the morphology, phase structure, crystallite size, specific surface area, pore structures, and photocatalytic activity of the microspheres were investigated. The results indicated that the as-obtained TiO2/C composite hollow spheres generally exhibit bimodal mesopore size distribution with their peak intra-aggregated mesopore size in the range of 2.3–4.5 nm and peak interaggregated mesopore size in the range of 5.7–12.7 nm, depending on specific calcination time. The daylight-induced photoactivity of as-obtained hollow TiO2/C microspheres generally exceeds that of Degussa P25. The influences of calcination time on the photoactivity are discussed in terms of carbon content, phase structures, and pore structures.

Frequent oil spills have caused severe environmental and ecological damage. Effective cleanup has become a complex challenge owing to the poor flowability of viscous crude oils. The current method of solar heating to reduce the viscosity of heavy oil is only suitable during sunny days, while the use of Joule heating is limited by the risk of direct exposure to high-voltage electricity. Herein, we demonstrate a noncontact electromagnetic induction and solar dual-heating sponge for the quick, safe, and energy-saving cleanup of ultrahigh-viscosity heavy oil. The resulting sponge with magnetic, conductive, and hydrophobic properties can be rapidly heated to absorb heavy oil under alternating magnetic fields, solar irradiation, or both of these conditions. By constructing theoretical models and fitting the actual data, an in-depth analysis of induction and solar heating processes is carried out. The sponge has excellent resilience and stability, indicating its reusability, fast and continuous adsorption (16.17 g in 10 s), and large capacity (75-81 g/g, the highest value ever) for soft asphalt (a highly viscous crude oil). This work provides a new noncontact dual-heating strategy for heavy oil cleanup, in which absorbents use induction heating during an emergency and then switch to partial or full solar heating to save energy in sunny conditions. ENVIRONMENTAL IMPLICATION: Heavy oils stranded on the beach or floating on water can kill underwater plants by blocking sunlight, or trap water birds and other animals. Heavy oil also contains aromatic substances that are toxic to aquatic organisms. Although oil spills near shallow water cannot be cleaned up by fences or other machinery, an oil adsorbent can deal with this problem. However, common adsorbents cannot effectively absorb high-viscosity oils, such as heavy oil. In this paper, an induction and solar dual-heating sponge is developed for the effective cleanup of high-viscosity oil.

A clean green, efficient and facile protocol was developed for the synthesis of a series of 2,3-dihydropyrido[2,3-d]pyrimidin-4(1H)-ones in water with good yield by the reaction of 2-amino-nicotinonitriles with carbonyls catalyzed by DBU under microwave irradiation. The DBU–H2O system can be recycled five times without activity loss.

AbstractSolar evaporation has attracted considerable interest to alleviate the shortage of water resources in the past few years. Lots of works have been done focusing on evaporation materials, rate, and efficiency, however, little attempts have been made to remove the harmful volatile organic compounds (VOCs), a kind of contamination that inevitably evaporate and condense alongside with water, which seriously affect the distilled water quality. This perspective puts forward some technical ideas utilizing chemical or physicochemical methods, aiming at the development of multifunctional composite materials, and forming an integrated evaporation system, which manage to remove VOCs in situ at the interface of photothermal evaporation.image