Microalgae have been considered as an efficient microorganism for wastewater treatment with simultaneously bioenergy and high value-added compounds production. However, the high energy cost associated with complicated biorefinery (e.g. microalgae cultivation, harvesting, drying, extraction, conversion, and purification) is a critical challenge that inhibits its large-scale application. Among different nutrition (e.g. carbon, nitrogen and phosphorous) sources, food processing wastewater is a relative safe and suitable one for microalgae cultivation due to its high organic content and low toxicity. In this review, the characteristic of different food wastewater is summarized and compared. The potential routes of value-added products (i.e. biofuel, pigment, polysaccharide, and amino acid) production along with wastewater purification are introduced. The existing challenges (e.g. biorefinery cost, efficiency and mechanism) of microalgal-based wastewater treatment are also discussed. The prospective of microalgae-based food processing wastewater treatment strategies (such as microalgae-bacteria consortium, poly-generation of bioenergy and value-added products) is forecasted. It can be observed that food wastewater treatment by microalgae could be a promising strategy to commercially realize waste source reduce, conversion and reutilization.

The experimental and numerical investigations of single drop in liquid/liquid extraction system have been reviewed with particular focus on experimental techniques and computational fluid dynamic simulation approaches. Comprehensive surveys of available experimental techniques and numerical approaches for single drop rising and falling were given. Subsequently, single drop mass transfer was also reviewed both experimentally and numerically. Additionally, single drop breakage and coalescence process and the influencing factors were summarized and compared, so as to establish sub-models for population balance model. Future directions on single drop mass transfer, drop breakage and coalescence were suggested. It is believed that the single drop is a powerful tool to assist extraction process design from lab-scale to pilot-scale.

To investigate the effect of regenerative cooling channel geometry on pyrolysis of endothermic hydrocarbon fuel, a series of supercritical pyrolysis experiments of n-decane in the rectangular and circular tubes were conducted. Moreover, sensitivity analysis of production of propylene and methane as well as CFD simulation were also done. The results showed that gas yield and conversion in the circular tube with an inner diameter of 2 mm had a similar tendency with the one of 1.5 mm in inner diameter. The conversion in the circular tube was much less than that in the rectangular tube at the same outlet temperature. The heat sink of the rectangular tube at the same outlet temperature was larger than that of circular tubes, but the temperature at the corner of the rectangular tube was relatively high. According to the experimental data of the test tubes, a correlation between the conversion and the temperature in the rectangular and circular tubes at the same outlet temperature was fitted, providing a reference for the design of regenerative cooling channels.

The subgrid-scale effects on particle motion were investigated in forced isotropic turbulence by DNS and priorLES methods. In the DNS field, the importance of Kolmogorov scaling to preferential accumulation was validated by comparing the radial distribution functions under various particle Stokes numbers. The prior-LES fields were generated by filtering the DNS data. The subgrid-scale Stokes number (St_SGS) is a useful tool for determining the effects of subgrid-scale eddies on particle motion. The subgrid-scale eddies tend to accumulate particles with St_SGS <1 and disperse particles with 1 < St_SGS < 10. For particles with St_SGS ≫ 1, the effects of subgrid-scale eddies on particle motion can be neglected. In order to restore the subgrid-scale effects, the Langevin-type stochastic model with optimized parameters was adopted in this study. This model is effective for the particles with St_SGS >1 while has an adverse impact on the particles with St_SGS <1. The results show that the Langevin-type stochastic model tends to smooth the particle distribution in the isotropic turbulence.

The shell side flow fields of both sextant and trisection helical baffle heat exchangers are presented on meridian and multilayer hexagon slices. It verifies that the performance of sextant schemes is better than those of the other kinds of helical baffle heat exchangers. The main mechanisms are due to the restricted leakage flow in the minimized gaps with increased baffle number and by one row of tubes dampen the leakage flow in the circumferential overlapped area of the adjacent helical baffles. The performance features were simulated on two different angled sextant helical heat exchangers and each compared with two trisection ones of either identical helical pitch or identical incline angle. The results verified that the performances of helical heat exchangers are mainly determined by the helical pitch rather than the baffle incline angle. The average values of comprehensive index h_oΔp_o^-1/3 of the trisection helical schemes T-24.1° and T-29.7° are correspondingly 3.47% and 3.34% lower than those of the sextant ones X-20° and X-25° with identical helical pitches. The comparison results show that the average values of shell side h.t.c. h_o and comprehensive index h_oΔp_o^-1/3 of the optimal dual helix sextant scheme DX30° are respectively 7.22% and 23.56% higher than those of the segment scheme S100.

Amine-based absorption/stripping is one of the promising technology for CO₂ capture from natural and industrial gas streams. During the process, amines and CO₂ undergo irreversible reactions to produce undesired compounds, which cause corrosion, foaming, increased viscosity and breakdown of equipment, ultimately contributing to the economic loss and environmental pollution. In this study, the thermal degradation of aqueous diethanolamine in the presence and absence of dissolved CO₂ was investigated. The experiments were performed in stainless steel cylinders. The results show that thermal degradation in the absence of CO₂ was a slow process; triethanolamine, and tris(2-aminoethyl)amine were only the degradation products identified in the mixture In addition, the rate of degradation was very low, only 3% degradation was observed after 4 weeks. But in the presence of CO₂, sixteen degradation products were identified, nine of which were new degradation products reported for the first time in this study. The 3-(2-hydroxyethyl)-2-oxazolidinone, 1,4-bis(2-hydroxyethyl) piperazine and triethanolamine were the most abundant degradation products. The remaining DEA concentration after 4 weeks was about 20% of the total amine concentration. The most probable degradation reactions and their mechanisms are also proposed.

In this work, a techno-economic study for the solvent based extraction of methacrylic acid from an aqueous solution is presented. The involved phase equilibrium calculations in process design are verified by measured experimental data. First, experiments are conducted with different solvent candidates to measure LLE (liquid-liquid equilibrium) data and to establish the effects of extraction temperature and dosage of solvent. Next, the binary interaction parameters for the UNIQUAC model to be used for equilibrium calculations are fine-tuned with measured data. Then, a process for the solvent based extraction of methacrylic acid recovery is designed and verified through simulation with the regressed UNIQUAC model parameters. The optimal configuration of the process flowsheet is determined by minimizing the total annualized cost. Among the three solvent candidates considered-cyclohexane, hexane and toluene-the highest efficiency and the lowest total annualized cost is found with toluene as the solvent.

Inefficient separation of inorganic salts and organic matters in crystallization mother liquor is still a problem to industrial wastewater treatment since the high salinity significantly impedes organic pollutant degradation by oxidation or incineration. In the study, acidification combined electrodialysis (ED) was attempted to effectively separate Cl^- ions from organics in concentrate pulping wastewater. Membrane's rejection rate to total organic carbon (TOC) was 85% at wastewater intrinsic pH=9.8 and enhanced to 93% by acidifying it to pH=2 in ED process. Negative-charged alkaline organic compounds (mainly lignin) could be liberated from their sodium salt forms and coagulated in acidification pretreatment. Neutralization of the organic substances also made their electro-migration less effective under electric driving force and in particular improved separation efficiency of chloride and organics. After acid-ED coupled treatment (pH=2 and J=40 mA·cm^-2)[TOC] remarkably reduced from 1.315 g·L^-1 to 0.048 g·L^-1 and[Cl^-] accumulated to 130 g·L^-1 in concentrate solution. Recovery rate of NaCl was 89% and the power consumption was 0.38 kW·h·kg^-1 NaCl. Irreversible fouling was not caused as electric resistance of membrane pile maintained stably. In conclusion, acidic-ED is a practical option to treat salinity organic wastewater when current techniques including thermal evaporation and pressure-driven membrane separation present limitations.

Ultrasonic-assisted extraction (UAE) combined with medium pressure liquid chromatography (MPLC) was designed for carbazole separation from anthracene slag (AS). The effects of liquid/solid ratio, temperature, and extraction times on carbazole separation were investigated. When using CCl₄ and ethyl acetate as extraction solvents and combining with MPLC, carbazole recovery and purity are 75.1% and 95.4%, respectively. The mechanism for carbazole separation were presumed by examining intermolecular interactions such as N-H…π, π-π, and C-Cl…π interactions. These results demonstrate that UAE/MPLC has a considerable potential as a green and promising strategy for separating and purifying carbazole and other chemicals from AS.

The separation of Ca²⁺ and Mg²⁺ ions from phosphoric acid-nitric acid aqueous solution is very significant for the neutralization process of nitrophosphate fertilizer. This paper studied the adsorption equilibrium, kinetics, and dynamic separation of Ca²⁺ and Mg²⁺ ions by strong acid cation resin, and the effects of phosphoric acid and nitric acid on the adsorption process were investigated. The results reveal that the adsorption process of Ca²⁺ and Mg²⁺ ions in pure water on resin is in good agreement with the Langmuir isotherm model and their maximal adsorption capacities are 1.86 mmol·g^-1 and 1.83 mmol·g^-1, respectively. The adsorption kinetics of Ca²⁺ and Mg²⁺ ions on resin fits better with the pseudo-first-order model, and the adsorption equilibrium in pure water is reached within 10 min contact time, while at the present of phosphoric acid, the adsorption rate of Ca²⁺ and Mg²⁺ ions on resin will go down. The dynamic separation experiments demonstrate that the designed column adsorption is able to undertake the separation of metal ions from the mix acids aqueous solution, but the dynamic operation should control the flow rate of mix acid solution. Besides nitric acid solution was proved to be effective to completely regenerate the spent resin and achieve the recyclable operation of separation process.

In this work, the mass transfer characteristics of two immiscible fluids were investigated in a rotating helical microchannel with hydraulic diameter of 932 μm. Aqueous phosphoric acid solution and 80% tri-n-butyl phosphate (TBP) in kerosene were selected for the investigation of mass transfer performance in quartz glass/high density polyethylene (HDPE) microchannel. High dispersion between the two immiscible fluids can be obtained in the microchannel due to the intensifying action of centrifugal force, and the majority of the droplets with average diameter of 20-100 μm were produced in the microchannel. The flow rate and rotation speed were found to have great effects on the extraction efficiency and average residence time. The empirical correlation of average residence time based on experimental data was developed by theoretical analysis and data fitting method, and a mathematical model of the mass transfer coefficient in dispersed phase was proposed.

The aminolysis of ethyl acetate was promoted significantly via continuous reaction in a tubular reactor. N-propylacetamide was thus synthesized without presence of solvent and catalyst. The optimum conditions were obtained as follows:the reaction temperature is 218℃, the reaction pressure is 3.5 MPa, the molar ratio (ethyl acetate:N-propylamine) is 1:1, and the residence time is 350 min. Accordingly, the conversion of ethyl acetate is up to 94.8%. Furthermore, the kinetics of the rapid reaction stage (when the conversion of ethyl acetate is 20%-80%) can be expressed as lnk--4629:44 1/T + 2:1366, and the apparent activation energy is E_a=38489 J·mol^-1.

Kaolin as a raw material for mesoporous support was firstly modified by calcination, acid treatment, and then was used to prepare nickel catalysts. The amount of alumina which was activated in kaolin during thermal treatment and then leached out in the acid was different. XRD pattern of the kaolin calcined at 600℃ or 900℃ exhibited only the diffraction peaks for amorphous silica and quartz while that calcined at 1100℃ showed obvious peaks for γ-Al₂O₃. Therefore, the nickel-based catalysts exhibited different physic-chemical properties. Atmospheric syngas methanation over the catalysts clarified an activity order of CA-1100 > CA-900 > CA-1400 > CA-600 > KA ≈ 0 at temperatures of 350-650℃ and a space velocity of 120 L·g^-1·h^-1. Metallic nickel with small diameter which has medium interaction with the modified kaolin and is well dispersed on the support would have reasonably good activity and carbon-resistance for syngas methanation.

The deactivation of Ni/SiO₂-Al₂O₃ catalyst in hydrogenation of crude 1,4-butanediol was investigated. During the operation time of 2140 h, the catalyst showed slow activity decay. Characterization results, for four spent catalysts used at different time, indicated that the main reason of the catalyst deactivation was the deposition of carbonaceous species that covered the active Ni and blocked mesopores of the catalyst. The TPO and SEM measurements revealed that the carbonaceous species included both oligomeric and polymeric species with high C/H ratio and showed sheet. Such carbonaceous species might be eliminated through either direct H₂ reduction or the combined oxidation-reduction methodologies.

Direct propylene epoxidation with H₂ and O₂, an attractive process to produce propylene oxide (PO), has a potential explosion danger due to the coexistence of flammable gases (i.e., C₃H₆ and H₂) and oxidizer (i.e., O₂). The unknown explosion limits of the multi-component feed gas mixture make it difficult to optimize the reaction process under safe operation conditions. In this work, a distribution method is proposed and verified to be effective by comparing estimated and experimental explosion limits of more than 200 kinds of flammable gas mixture. Then, it is employed to estimate the explosion limits of the feed gas mixture, some results of which are also validated by the classic Le Chatelier's Rule and flammable resistance method. Based on the estimated explosion limits, process optimization is carried out using commercially high and inherently safe reactant concentrations to enhance reaction performance. The promising results are directly obtained through the interface called gOPT in gPROMS only by using a simple, easy-constructed and mature packed-bed reactor, such as the PO yield of 13.3%, PO selectivity of 85.1% and outlet PO fraction of 1.8%. These results can be rationalized by indepth analyses and discussion about the effects of the decision variables on the operation safety and reaction performance. The insights revealed here could shed new light on the process development of the PO production based on the estimation of the explosion limits of the multi-component feed gas mixture containing flammable gases, inert gas and O₂, followed by process optimization.

A fuzzy comprehensive assessment method of running condition was constructed and applied to a large-scale centrifugal compressor set in a petrochemical corporation aiming at the monitoring and early warning of abnormal conditions in industry. The maximal information coefficient (MIC) correlation analysis of indexes was introduced to determine the independent indexes to be assessed, and the dynamic deterioration degree was calculated using the predicted independent indexes by the second-order Markov chain model. The fuzzy membership degree weighting method was employed to assess the running condition of all units in the set. Simple and direct radar chart was used to visualize condition assessment grades. Results showed that the proposed fuzzy comprehensive assessment method successfully assessed the running condition of the set. The constructed method achieved 10 min earlier alarm than the traditional threshold alarm occurred at the specific moment of 00:44 on April 7 of 2018. The method would provide a valuable tool and have a wide engineering application in ensuring the safety and reliability of industrial production.

The preparation of sulfoaluminate cementitious materials (SCM) is a promising way to massively utilize solid wastes. Iron phases are significant in SCM system but the thermodynamic data of some key minerals, such as 6CaO·Al₂O₃·2Fe₂O₃ (C₆AF₂) and 6CaO·2Al₂O₃·Fe₂O₃ (C₆A₂F), are missing, which greatly hinders the SCM optimization in a theoretical way. This work, for the first time, calculated the standard formation enthalpy, Gibbs free energy of formation, entropy and molar heat capacity for C₆AF₂ and C₆A₂F and lowered the errors to the least with the reference of C₄AF data in the literature. By building the function diagram of Gibbs free energy changes with temperature for the basic iron phase formation reactions with the obtained thermodynamic data, it is proved that the formation likeliness of C₆AF₂ is higher than that of C₆A₂F, as is accordant to the literatures and verifies the correctness of obtained data. This work provides a good theoretical foundation to optimize SCM mineral system and to study relevant mechanism deeply.

The density and viscosity of 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM][BF₄] and 1-butyl-3-methylimidazolium chloride [BMIM][Cl] and their binary mixtures within the temperatures from 303.15 K to 323.15 K and at ambient pressure were determined in this work. The temperature dependences of density and viscosity were satisfactorily described with the linear model and the Vogel-Tammann-Fulcher type equation, respectively. The molar volume and viscosity of binary IL mixtures were predicted through ideal mixing rules showing that almost null deviations for IL mixtures were observed and their mixing was remarkably close to linear ideal behavior in the molar volumes, while comparatively large errors in viscosity occurred. Additionally, the molar volume of the investigated pure ILs and their mixtures could well be predicted by a predictive model presented by Valderrama et al. (Fluid Phase Equilib., 275 (2009) 145).

In this work, the solubility data and liquid-phase mass transfer coefficients of hydrogen (H₂), methane (CH₄) and their mixtures in vacuum gas oil (VGO) at temperatures (353.15-453.15 K) and pressures (1-7 MPa) were measured, which are necessary for catalytic cracking process simulation and design. The solubility of H₂ and CH₄ in VGO increases with the increase of pressure, but decreases with the increase of temperature. Henry's constants of H₂ and CH₄ follow the relation of ln H=-413.05/T + 5.27 and ln H=-990.67/T + 5.87, respectively. The molar fractions of H₂ and system pressures at different equilibrium time were measured to estimate the liquid-phase mass transfer coefficients. The results showed that with the increase of pressure, the liquid-phase mass transfer coefficients increase. Furthermore, the solubility of H₂ and CH₄ in VGO was predicted by the predictive COSMO-RS model, and the predicted values agree well with experimental data. In addition, the gas-liquid equilibrium (GLE) for H₂ + CH₄ + VGO system at different feeding gas ratios in volume fraction (i.e., H₂ 85% + CH₄ 15% and H₂ 90% + CH₄ 10%) was measured. The selectivity of H₂ to CH₄ predicted by the COSMO-RS model agrees well with experimental data. This work provides the basic thermodynamic and dynamic data for fuel oil catalytic cracking processes.

The reduction of nitrate using internal circulation micro-electrolysis technology (ICE) was investigated. The effect of the reaction time, initial pH, Fe/C ratio, and aeration rate on the nitrate reduction was investigated using a single factor experiment. Based on the results of the single factor experiment, a response surface methodology (RSM) was applied to optimize the N₂ generation selectivity. The effects and interactions of three independent variables were estimated using a Box-Behnken design. Using the RSM analysis, a quadratic polynomial model with optimal conditions at pH=8.8, Fe/C=1:1, and an aeration rate of 30 L·min^-1 was developed by means of the regression analysis of the experimental data. Using the RSM optimization, the optimal conditions yielded a N₂ generation selectivity of 72.0%, which is in good agreement with experimental result (73.2%±0.5%) and falls within the 95% confidence interval (IC:66.8%-77.3%) of the model results. This indicates that the model obtained in this study effectively predicts the N₂ generation selectivity for nitrate reduction by the ICE process, thus providing a theoretical basis for process design.

A new method for nitric oxide (NO) removal was developed by combining dielectric barrier discharge (DBD) and negative pulse corona (NPC). The effects of gas composition (O₂, CO₂, and H₂O) on NO removal were investigated with this method, and the effect of alcohols (methanol and ethanol) addition on NO removal was also investigated as well as the reaction mechanisms to enhance the NO removal efficiency. The experimental results showed that O₂, CO₂, and H₂O had obvious inhibition effects on NO removal, and the negative effects were in the following order:O₂ > CO₂ > H₂O. The addition of methanol or ethanol in the reaction system could mitigate the negative effects of O₂, CO₂, and H₂O on NO removal, and also eliminated the production of NO₂. The positive effect of alcohols addition with DBD-NPC denitration method was also validated in the simulated flue gas, in which the NO_x (NO, NO₂) was mainly converted into N².

The electrochemical behavior of lanthanide elements deposited on liquid zinc cathodes was studied using cyclic voltammetry (CV) and open circuit chronopotentiometry (OCP). We observed a "bimodal effect" in the equilibrium deposition potentials of zinc with lanthanides. A mathematic equation is derived to illustrate the relationship between the equilibrium potential of the intermetallic compounds formed by lanthanide elements and zinc and their atomic radius. This equation is not only applicable to lanthanide elements but also hold for other elements such as alkali metal lithium, alkaline earth metal magnesium, calcium and transition metal niobium, which have crucial theoretical significance for the electrolysis of intermetallic compounds, the separation, and extraction of metals.

Pd-doped organosilica membranes were prepared by controlling calcination atmospheres (i.e. POS-Air, POS-N₂, POS-H₂, POS-H₂/N₂) to tailor their networks for improving their gas separation performance. This study shows that Pd (II) could be only maintained under non-reductive calcination atmosphere, while inert and reducing calcination atmosphere is more beneficial to maintain organosilica moieties in POS networks. POS-H₂/N₂ membrane showed the optimal H₂ separation performance that its permselectivities for H₂/CO₂, H₂/N₂, H₂/CH₄ and H₂/SF₆ are 15.0, 96.7, 173.0 and 3400.0, respectively. Moreover, it is found that H₂ molecules pass through the four membranes based on activated diffusion, while CO₂ molecules permeation through POS-N₂ and POS-Air membrane is dominated by surface diffusion. This work may provide insight into the understanding of the calcination atmosphere effect on gas separation performance of metal-doped organosilica membranes.

A novel antibacterial acrylate polymer composite modified with capsaicin was successfully synthesized by a two-step reaction. Capsaicin and acryloyl chloride were firstly esterified, and then applied to solution polymerization with acrylate monomers and styrene. The yield of the esterified products was about 85.3%. The polymer was characterized by Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), thermogravimetric analysis (TGA), contact angle (CA) and antibacterial ring tests. The number-average molecular weight (M_n) of the polymer was 27214, based on the capsaicin-acrylate dosage of 6.5 wt%. The TGA revealed a stable thermal property. The contact angles of the polymers films on tinplate increased from 77.5° to 86.2° with the increasing amount of capsaicin-acrylate. The antibacterial tests demonstrated excellent antimicrobial capability of the polymers.

In recent years, the excessive use of antibiotics has become a serious problem for human health. BiVO₄ regarded as one of the most promising visible-light-driven photocatalysts was used to degrade the antibiotics. In this paper, we fabricated Bi/BiVO₄ plasmonic photocatalysts which enhanced the photocatalytic activity of BiVO₄ for degradation of tetracycline (TC) antibiotic. The Bi/BiVO₄ photocatalysts were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy and high-resolution transmission electron microscopy. In addition, the photocatalytic experiment results show that the 0.04-Bi/BiVO₄ sample has the best photocatalytic activity for 2 times than the pure BiVO₄ photocatalyst. The cycle experiments, after four repetitions of the experiments, showed the sample still maintained a high photocatalytic activity. Finally, the photocatalytic reaction mechanism was also studied by free radical capture experiments and electron paramagnetic resonance spectroscopy.