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CO2 capture by stripping with aqueous amine is a well-understood and widely employed technology. However, there still exist several drawbacks in the practical applications, such as high energy cons...

Phase-change solvents exhibit the promising potential to reduce the regeneration energy for CO2 capture. In this paper, 3-dimethylaminopropylamine (DMAPA) with intramolecular primary and tertiary a...

A series of highly efficient, environmentally friendly, and low-cost FeaSbTiOx catalysts were prepared by a simple thermal hydrolysis method for the NH3-selective catalytic reduction (SCR) reaction...

A filter mesh was prepared by a facile biomimetic mineralization method with excellent superhydrophilic and underwater superoleophobic properties for the gravity-driven oil-water separations. It sh...

Molybdenum carbide catalysts over activated carbon with different crystal phases were synthesized under controllable carburization atmospheres and temperatures for transfer hydrogenation of Kraft l...

Engineering a heterojunction on a TiO2 surface (such as SnO2/TiO2) is an effective strategy to enhance photocatalytic activity, by facilitating charge separation. However, the traditional fabricati...

A route for the indirect carbonation of different minerals using (NH4)2SO4 (AS) as a recyclable reagent has been recently proposed. For saving energy, the extraction of alkaline components, such as...

CO2 emissions reduction has become a hot issue to relieve global warming in recent years. CO2 absorption with amines aqueous solutions is a promising method for its capture, and increasing CO2 capacity and reducing energy consumption are essential for its application. In this work, a data set of 29 different amines was regressed with genetic function approximation (GFA) and artificial neural network (ANN) algorithm to find a predictive quantitative relationship between amine structure and CO2 absorption capacity. Density functional theory (DFT) methods at levels B3LYP and 6-311+g (d,p) were used to optimize the structures. Both reactants and products were introduced in regression, and an optimal model with best relevance and predictability for CO2 absorption at 313 K was obtained and experimentally confirmed. Descriptors analysis showed that reducing the number of hydroxyl groups, increasing molecular mass, and changing steric effect of amine structure would increase its CO2 absorption capacity. Two new a...

The β-Mo2C on different carbon supports was prepared conveniently via direct H2 reduction or self-reduction for catalytic conversion of Kraft lignin into aromatic hydrocarbons, aromatic alcohols, a...

Amine-based CO2 postcombustion capture is a commercialized technology for recovery CO2 from flue gas, and the energy consumption is concentrated in the regenerative stage. The phase-change solvent system, monoethanolamine (MEA, absorbent) + solvent A (SA, solvent) + water (solvent), was investigated on the performances of CO2 absorption and desorption. CO2-rich solvent can be continuously separated for the feeding flow of the regeneration tower; thereby, it significantly reduces the energy of regeneration. The results show that the solvent with suitable composition can easily separate the CO2-rich phase from the solvent, and the CO2-rich phase accounts for more than 98% of the total CO2. At 293–333 K, the temperature has no significant effect on the absorption rate and phase equilibrium. The estimation of energy consumption shows that the reboiler work can be reduced by 43.6% compared with that using 20 wt % MEA aqueous solution.

Soda ash, as one of the most important chemicals, is mainly manufactured by the Solvay process. However, the Solvay process consumes energy at a rate of up to 9.7–13.6 GJ/ton Na2CO3. Here, we prese...

TiO2 pigments are widely used in paint industries. Inert coating layers were usually deposited on the TiO2 pigments to suppress the photocatalytic activity of TiO2, which can prevent the degradation of surrounding polymer molecules. However, the traditional wet chemical methods normally form thick films, which would impair the pigment properties of TiO2. In this work, SnO2 and SiO2 protective layers were grown on the TiO2 particle surface by low-temperature pulsed chemical vapor deposition. At temperatures

The unstable copper active sites and diffusion limitations of the current Cu-based catalysts are the key issues for the industrial ethylene carbonate (EC) hydrogenation reaction. Monolithic Cu-based catalysts were synthesized with the Cu/SiO2 nanoarrays embedded in cordierite channels via an in situ hydrothermal process for catalytic EC hydrogenation to methanol (MeOH) and ethylene glycol (EG). The monolithic catalysts exhibited superb activity, with an EC conversion of 99% along with EG and MeOH selectivity of 97% and 50%, respectively. The characterization indicated that the high activities are attributed to the high dispersion of Cu species, appropriate proportion of surface Cu+ and Cu0, and negligible influence of inner diffusion, while the high stabilities are ascribed to the regular nanoarray geometric structure and strong interactions between Cu species and SiO2. The Cu/SiO2 nanoarray monolithic catalysts represent a new idea combining the properties of nanocatalysts and engineering of the practica...

A new method coupling CO2 mineralization and solvent extraction was proposed and investigated to precipitate magnesium from high Mg/Li ratio brine. Organic amine was employed to extract HCl formed during the CO2 mineralization process and to realize continuous conversion of MgCl2 to precipitated MgCO3, thereby removing the magnesium contained in the brine. The effects of brine concentration, extractant, diluents, extractant concentration, phase ratio, and reaction temperature were systematically investigated. A blend of trioctylamine and isoamyl alcohol was used as the extractant and diluent, and the reaction parameters were optimized. The mechanism was proposed, and a stripping process was designed. Under the optimal conditions, the conversion of magnesium was as high as 67.41%, and the Mg/Li ratio of the raffinate decreased from 20 to 5.4.

Lotus leaves and rose petals are both typical natural superhydrophobic surfaces, with low and high adhesion, respectively. This fact inspires us to prepare superhydrophobic surfaces with different levels of adhesion on iron by mimicking their hierarchical structures through three simple steps: abrasion, calcination, and modification. A uniform and stable superhydrophobic iron surface with excellent adaptability and wearability can be obtained, and its adhesion is tunable. The results confirmed that superhydrophobicity and adhesion are both dependent on the synergy of the microscale and nanoscale patterns of the hierarchical structure generated by the designed abrasion and thermal treating. The adhesion level can be controlled by simply adjusting the abrasion program to obtain the desired microscale pattern with a proper ratio of height-to-width of the microstructure. This easy, inexpensive, and clean three-step method is widely applicable for different engineering metals and alloys and suitable for large-...

LiBr refrigerating systems are frequently used in industry, but the pipelines are easily corroded or blocked by the LiBr solution with high flow resistance. Here, a superhydrophobic Fe surface was proposed and tested for applicability. After constructing a rough Fe2O3 nanotube array on a Fe surface by the anodization process, a superhydrophobic Fe surface was obtained by silane modification. The as-prepared superhydrophobic surface exhibited excellent repulsion to LiBr solutions. The modified Fe foil showed a 3.35% decrease in thermal conductivity but a 99.2% improvement of anticorrosion protection efficiency. LiBr crystals deposited on this surface were easily detached. The flow resistance along the superhydrophobic surface was reduced to 50% of that along a pure Fe surface. The operation temperature of the system was broadened due to low blockage risk. The excellent thermal conductivity, anticorrosivity, drag reduction, and antifouling performance of the superhydrophobic Fe surface exhibits promise for ...

In this research, an experiment was conducted by introducing superhydrophobic surface into rolling spheronization granulation. The employed superhydrophobic surface was prepared with modification of an anodized Cu mesh with silane FAS-17 and exhibited excellent uniformity, adequate stability, and broad adaptability in the granulation scenario. Completely spherical molecular sieve granules with 99.85% sphericity and 2.53 mm diameter were obtained. The compressive strength of a single granule reached 7.402 N/ea. Only negligible residual mass and slight surface abrasion were observed in the granulation process. Force analysis confirmed that the staged motion behavior of droplets caused by the interaction between the slurry and the superhydrophobic surface benefited to the formation of spherical granules. Successful application of this process for granulation of other substances confirmed its wide suitability. With the advantages of easy fabrication, high-quality granules, and low cost, rolling-spheronization...

Antiscaling technology is necessary in order to prevent the performance loss and blockage of heat exchangers. In this research, a superhydrophobic CuO nanowire layer was prepared and utilized for antiscaling process of CaCO3 on the surface of copper. Modified with 1H,1H,2H,2H-perfluorodecyltriethoxysilane (FAS-17), the water contact angle on the CuO surface increased sharply from 4.5° ± 1° after anodization to 154° ± 2°, since the surface free energy decreased from 74.8 mJ/m2 for the hydrophilic surface to 0.2 mJ/m2 for the superhydrophobic surface. The scale inhibition performance of the surface of superhydrophobic CuO nanowires was confirmed since the corresponding scaling weight of deposited CaCO3 decreased significantly from 0.6322 mg/cm2 to 0.1607 mg/cm2. This attractive antiscaling effect of the modified superhydrophobic CuO nanowire surface should ascribe to the slow CaCO3 crystal nucleation rate, because of the low surface energy, low adhesion strength of CaCO3 crystal, and air film retained on th...

This paper describes a kinetic study on the sulfidation and regeneration of Mn/Al2O3 sorbent for high temperature H2S removal. The influence of the reactant gas compositions and temperatures on the sulfidation and regeneration behavior was systematically investigated in a thermogravimetric apparatus. The results show that the shrinking core model can be used to correlate with the experimental data. The sulfidation is mainly dominated by diffusion. Through the regressions of the initial sulfidation reaction data, the chemical reaction order, activation energy, and pre-exponential factor are 1, 37.42 kJ/mol, and 4.16 × 10–2 m/s, respectively, and the diffusion activation energy and pre-exponential factor are 57.23 kJ/mol and 6.41 × 10–5 m2/s, respectively. O2 regeneration has the same situation as sulfidation; the chemical reaction order, activation energy, and pre-exponential factor are 1, 24.62 kJ/mol, and 0.17 m/s, respectively, and the diffusion activation energy and pre-exponential factor are 122.44 kJ...

Photocatalytic processes are an environmentally friendly technology for treatment of persistent organic pollutants. However, the majority of current photocatalysts cannot utilize sunlight sufficiently to realize fast decomposition of organic pollutants. In this research, a silver oxide nanoparticle aggregation with superb photocatalytic performance under artificial light source and sunlight was prepared and characterized. The results showed that methyl orange (MO) was decomposed completely in 120 s under irradiation of artificial visible light, artificial ultraviolet light, and sunlight, and in 40 min under near-infrared (NIR) light. The superb photocatalytic performance of as-prepared silver oxide remained almost constant after reuse or exposure under sunlight. It was confirmed that the co-working effect of photogenerated hole and ozone anion radicals did play an important role in the process of MO photodegradation with the existence of Ag2O. The narrow band gap of Ag2O, less than 1.3 eV, resulted in the...

Biodiesel is a promising alternative biofuel, but the treatment of wastewater containing alkali catalyst and glycerol discharged from the washing unit operation increases the cost significantly. Here a novel continuous biodiesel production process with trace-amount alkali as the catalyst under the methanol subcritical condition was proposed and investigated. The optimal operation conditions of preliminary batch reaction experiment are temperature of 200 °C, catalyst concentration of 513 mg/kg, reaction time of 38 min, molar ratio of methanol to oil of 11.9:1, and system pressure of 1.5 MPa. The one-step conversion of raw oil in a batch reactor can reach up to 85.5%. The alkali residue in the biodiesel product can be further reduced by removing the methanol and washing by glycerol instead of by acid or water. The optimal weight ratio of glycerol to biodiesel is 1.5:1, and the residual alkali in the final ester product is about 4.6 mg/kg. The simulation and bench scale continuous experiment based on the opt...

With the objective of developing anticorrosive conductive polymeric coatings to combat microbially induced corrosion (MIC), a facile and green synthesis approach based on a thermally induced reaction was described. Thermal curing of polyaniline (PANI) was carried out from the silanized mild steel (MS) surface containing reactive epoxy groups, followed by thermally induced N-alkylation of PANI by hydrophobic 4-vinylbenzyl chloride (VBzCl) to produce biocidal functionality. The so-synthesized MS coupons with hydrophobic poly(vinylbenzyl chloride) (PVBC)–quaternized PANI bilayer coatings were investigated for their anticorrosive and antibacterial properties toward biocorrosion induced by sulfate-reducing bacteria (SRB). Antibacterial assay results revealed an evident decrease in the bacterial attachment and the formation of biofilm. The QPANI–PVBC bilayer coatings showed a high corrosion resistance (inhibition efficiency >97%) and stability to resist SRB-induced corrosion. Thus, the QPANI–PVBC bilayer coated...

We report an alternative technology for the mineralization of CO2 and production of soluble potash fertilizer via thermal activation of the insoluble K-feldspar with industrial waste of CaCl2 with lower energy consumption since the activation temperature was about 800–900 °C compared with the conventional temperature of 1300 °C. A remarkable K-extraction and CO2 mineralization ratio could be obtained at an appropriate activation temperature and content of additive CaCl2, which possessed the exchange of skeletal K+ with dissociative Ca2+ to form soluble K+ species, the collapse of K-feldspar framework, and the formation of intermediates (e.g., anorthite, pseudowollastonite, and wollastonite) to react with CO2. Characterization results (e.g., XRD, EDS, and SEM) indicated that pseudowollastonite and wollastonite were the major species to fix CO2. Moreover, the reaction principles of the K-extraction and CO2 mineralization were discussed, and a possible mechanism was proposed.

This article describes a novel CO2 mineralization approach using natural insoluble K-feldspar and phosphogypsum for the emission of CO2, reduction of phosphogypsum waste, and production of soluble potash. K-feldspar was activated with CaSO4 at high temperature and then mineralized with CO2 to extract potassium under hydrothermal conditions. Activation and mineralization conditions (e.g., ore/CaSO4 mass ratio, calcination and mineralization temperatures, initial pressure of CO2) were systematically investigated with an optical potassium extraction ratio of ∼87% and a CO2 mineralization ratio of ∼7.7%. A reaction mechanism was proposed based on the experimental results and the characterizations, such as polarized light microscopy, X-ray diffraction, and thermogravimetric and differential thermal analyses. This new methodology is a promising process and has the potential to reduce emissions of CO2 and phosphogypsum from a practical point of view.

The morphology and crystallization properties of poly(vinylidene fluoride) ultrafiltration membranes prepared by the phase inversion method were investigated under ultrasound-assisted conditions in a coagulation bath. All the membranes showed improved performance compared with that of the pristine membrane, including preferable morphology, higher porosity, and higher flux for water and a Rose Bengal (RB) aqueous solution. With an increase in the ultrasonic intensity, the flux of membranes for both water and RB aqueous solution increased gradually, while the rejection by all membranes was nearly 80%. The porosity was measured by the percentage water content. Phase separation was accelerated and macrovoids developed with an increase in ultrasonic intensity, resulting in an improvement in membrane porosity. The crystalline structure was assessed by wide-angle X-ray diffractometry and attenuated total reflectance Fourier transform infrared spectroscopy. It was also shown that the β crystalline phase was partl...

A novel strategy by combination of surface-initiated atom transfer radical polymerization (ATRP) and in situ chemical oxidative graft polymerization was employed to tether stainless steel (SS) with poly(4-vinylaniline)-polyaniline (PVAn-PANI) bilayer coatings for mitigating biocorrosion by sulfate-reducing bacteria (SRB) in seawater. A trichlorosilane coupling agent was first immobilized on the SS surfaces to provide sulfonyl halide groups for surface-initiated ATRP of 4-VAn. A subsequent grafting of PANI onto the PVAn-grafted surface was accomplished by in situ chemical oxidative graft polymerization of aniline. The PVAn-PANI bilayer coatings were finally quaternized by hexylbromide to generate biocidal functionality. The so-synthesized SS surface was found to significantly reduce bacterial adhesion and biofilm formation. Electrochemical results revealed that the PVAn-PANI modified SS surface exhibited high resistance to biocorrosion by SRB. With the inherent anticorrosion capability and antibacterial properties of quaternized PVAn-PANI bilayers, the functionalized SS substrates are potentially useful to steel-based equipment under harsh marine environments.

Kerosene-in-water emulsions were de-emulsified by narrow plate-type microchannels. The emulsions with different Sauter diameters of 5 or 10 μm were formed by high-shear homogenization method and pa...

The effect of acid treatment on the high-temperature oxidation behavior of Fe−Cr−Al alloy has been examined with oxidation tests and various characterization techniques. Acid treatment effectively improves the stability of the alloy in a high-temperature oxidation environment. After the treatment, the alloy oxidizes at a higher rate in the induction period and a lower rate in the subsequent time period. A passivative oxide layer was determined to be better formed during high-temperature oxidation on the surface of the acid-treated alloy, which suppressed further oxidation. It was observed that the oxidation rate of the alloy at high temperature can be described precisely by the Quadakkers equation.

Scaling is unavoidable during hydrocarbon oxidation catalyzed by metal salts, such as the liquid-phase oxidation of toluene to produce benzoic acid. Scaling often results in many operation problems...

The liquid-phase oxidation of toluene by air is an environmentally benign process to produce benzoic acid and benzaldehyde. In a bubble column (diameter of 48 mm) reactor, the kinetics of the oxida...

A modified process for the production of ammonium phosphate fertilizer from the middle-quality phosphate ore was proposed. In this process, dilute phosphoric acid produced by the dihydrate process is neutralized by ammonia and the slurry is then concentrated. This effectively solved the scaling in the heater during phosphoric acid concentration. Moreover, the middle-quality phosphate ore containing impurities can now be used. The pilot test showed that the less corrosive, longer operation periodic time, less scaling, and easy cleaning made it superior to the traditional process.