The influence of interlayer anions such as NO₃^-, SO₄^2- and Cl^- on Mg-Al hydrotalcites for Cr(VI) removal from aqueous solution was studied. The structure of the prepared LDHswas characterized by XRD, SEM, FTIR, TGA, BET surface area and pHzpc. The sorbent ability and sorption mechanisms were also investigated. The LDHs exhibit high removal for Cr(VI), and the sorbed amount depends on the nature of interlayer anion, which decreased in the following order: NO₃^- > Cl^- > SO₄^2-. Nitrate-containing LDH reached a Cr(VI) sorption equilibrium within only 30 min. The effects of operating conditions, including initial concentration, solution pH, agitation time and sorbent amount have been studied in batch mode. The optimum conditions were observed at an initial concentration of 100 mg·L^-1, pH=6, agitation timeof 60 min and a sorbent dose of 2 g·L^-1. The equilibriumdatawere fitted to the Langmuir, Freundlich and Dubinin-Radushkevich isothermmodels. The Langmuir modelwas found to sufficiently describe the sorption process, offering a maximum sorption capacity of 71.91 mg·g^-1. The sorption kinetic follows pseudo-second-order reaction with high accuracy. Thermodynamic parameters suggested that the sorption process is spontaneous and endothermic in nature.

Adsorption process is acknowledged as an effective option for phenolic wastewater treatment. In this work, the activated carbon (AC) samples after thermalmodification were prepared by usingmuffle furnace. The phenol adsorption kinetics and equilibriummeasurementswere carried out under static conditions at temperature ranging from 25 to 55℃. The test results show that the thermal modification can enhance phenol adsorption on AC samples. The porous structure and surface chemistry analyses indicate that the decay in pore morphology and decrease of total oxygen-containing functional groups are found for the thermal modified AC samples. Thus, it can be further inferred that the decrease of total oxygen-containing functional groups on the modified AC samples is the main reason for the enhanced phenol adsorption capacity. For both the raw sample and the optimum modified AC sample at 900℃, the pseudo-second order kinetics and Langmuir models are found to fit the experimental data verywell. Themaximumphenol adsorption capacity of the optimummodified AC sample can reach 144.93 mg·g^-1 which is higher than that of the raw sample, i.e. 119.53 mg·g^-1. Adsorption thermodynamics analysis confirms that the phenol adsorption on the optimum modified AC sample is an exothermic process and mainly via physical adsorption.

Filtration is one of the most effective methods to remove suspended fine particles from air. In filtration processes, pressure drop of compact dust cake causes problems in efficiency and economy, which has received increasing attention and still remains challenging. In this study,we developed a novel technique to intensify the filtration of fine particles with efficient humidification. Two strategies for humidification, including ultrasonic atomization and steam humidification (controlling of ambient humidity), were employed and proved to be both effective. The regeneration frequency of the filter could be reduced by 55%with ultrasonic atomization,while steamhumidification could lead to a 78% reduction in regeneration frequency. The effect of operating conditions on pressure drop and the mass loading during filtration were investigated. The dust cake showed a loose and porous structure with an optimized droplet-to-particle ratio.With the ratio of 1.53 and 0.0282, themaximum mass loadingwas 552 g·m^-2 upon the ultrasonic atomization and 720 g·m^-2 upon the steam humidification. The results show that humidification could slow down the increase of pressure drop during filtration and improve the efficiency of process.

Different VSA (Vacuum Swing Adsorption) cycles and process schemes have been evaluated to find suitable process configurations for effectively separating CO₂ from flue gases from different industrial sectors. The cycles were studied using an adsorption simulator developed in our research group, which has been successfully used to predict experimental results over several years. Commercial zeolite APGIII and granular activated carbon were used as the adsorbents. Three-bed VSA cycles with- and without-product purge and 2-stage VSA systems have been investigated. It was found that for a feed gas containing 15% CO₂ (representing flue gas from power plants), high CO₂ purities and recoveries could be obtained using a three-bed zeolite APGIII VSA unit for one stage capture, but with more stringent conditions such as deeper vacuum pressures of 1-3 kPa. 2-stage VSA process operated in series allowed us to use simple process steps and operate at more realistic vacuum pressures. With a vacuum pressure of 10 kPa, final CO₂ purity of 95.3% with a recovery of 98.2% were obtained at specific power consumption of 0.55 MJ·(kg CO₂)^-1 from feed gas containing 15% CO₂. These numbers compare very well with those obtained from a single stage process operating at 1 kPa vacuum pressure. The feed CO₂ concentration was very influential in determining the desorption pressure necessary to achieve high separation efficiency. For feed gases containing >30% CO₂, a singlestage VSA capture process operating at moderate vacuum pressure and without a product purge, can achieve very high product purities and recoveries.

Catalysts CuO_x/γ-Al₂O₃-IH and CuO_x/γ-Al₂O₃-IM were prepared, characterized, and tested for styrene combustion in the absence and presence of water vapor. The effect of copper valence of the catalysts on the catalytic activity for styrene combustion was discussed using the theory of hard soft acids and bases (HSAB). The results showed that the existence of water vapor in feed stream inhibited the catalytic activity for styrene combustion due to the competition adsorption of water molecule. HSAB theory confirmed that the local soft acidity of the catalyst CuO_x/γ-Al₂O₃-IH was much stronger than that of the catalyst CuO_x/γ-Al₂O₃-IM because of the higher content of soft acid Cu⁺ on its surface, which increased the adsorption ability toward soft base of styrene and reduced the adsorption toward hard base of water vapor, and thus increased the catalytic activity for styrene combustion and weakened the negative influence of water vapor.

This paper reports on the synthesis of copper doped sulfated titania nano-crystalline powders with varying (2.0%-10.0%, by mass) by single step sol gel method. The synthesized photo catalyst has been characterized by employing various techniques like X-ray Diffraction (XRD), Ultraviolet-Visible Diffuse Reflection Spectroscopy (UV-Vis DRS), X-ray Photoelectron Spectroscopy (XPS), Scanning ElectronMicroscopy (SEM), Energy Dispersive Spectrometry (EDS), Fourier Transform Infrared Spectroscopic Studies (FT-IR), and Transmission Electron Microscopy (TEM). Fromthe XRD and TEMresults, all the sampleswere reported in anatase phasewith reduction in particle size in the range of 7 to 12 nm. SEMindicated the change inmorphology of the particles. The presence of copper in titania lattice was evidenced by XPS. From UV-Vis DRS and FT-IR studies indicated that prominent absorption shift is observed towards visible region (red shift), the entry of Cu²⁺ into TiO₂ lattice as a substitutional dopant and SO₄^2- ions were covalently bonded with Ti⁴⁺ on the surface of the copper doped titania respectively.
The photocatalytic activity studies were investigated by consideringmethyl orange (MO) as dye pollutant in the presence of the visible light. The effect of various parameters like effect of dosage of the catalyst, dopant concentration, pH of the solution, and concentration of the dye was studied in detail.

Activated carbon was tested as metal-free catalyst for hydrochlorination of acetylene in order to circumvent the problem of environment pollution caused by mercury and high cost by noble metals. Oxygen-doped and nitrogen-doped activated carbons were prepared and characterized by XPS, TPD and N₂ physisorption methods. The influences of the surface functional groups on the catalytic performancewere discussed base on these results. Among all the samples tested, a nitrogen-doped sample, AC-n-U500, exhibited the best performance, the acetylene conversion being 92% and vinyl chloride selectivity above 99% at 240℃ and C₂H₂ hourly space velocity 30 h^-1. Moreover, the AC-n-U500 catalyst exhibited a stable performance during a 200 h test with a conversion of acetylene higher than 76% at 210℃ at a C₂H₂ hourly space velocity 50 h^-1. In contrary, oxygen-doped catalyst had lower catalytic activities. A linear relationship between the amount of pyrrolic-N and quaternary-N species and the catalytic activity was observed, indicating that these nitrogen-doped species might be the active sites and the key in tuning the catalytic performance. It is also found that the introduction of nitrogen species into the sample could significantly increase the adsorption amount of acetylene. The deactivation of nitrogendoped activated carbon might be caused by the decrease of the accessibility to or the total amount of active sites.

Nowadays artificial neural networks (ANNs) with strong ability have been applied widely for prediction of nonlinear phenomenon. In this work an optimized ANN with 7 inputs that consist of temperature, pressure, critical temperature, critical pressure, density,molecular weight and acentric factor has been used for solubility prediction of three disperse dyes in supercritical carbon dioxide (SC-CO₂) and ethanol as co-solvent. Itwas shown how a multi-layer perceptron network can be trained to represent the solubility of disperse dyes in SC-CO₂. Numeric Sensitivity Analysis and Garson equation were utilized to find out the degree of effectiveness of different input variables on the efficiency of the proposedmodel. Results showed that our proposed ANN model has correlation coefficient, Nash-Sutcliffe model efficiency coefficient and discrepancy ratio about 0.998, 0.992, and 1.053 respectively.

Sodium silicate and that calcined at 400℃ for 2 h were used to catalyze the transesterification of cottonseed oil with methanol. Calcined sodium silicate (CSS) catalyst exhibited much higher catalytic activity and stability. A maximum biodiesel yield of 98.9% was achieved at methanol/oil mole ratio of 12:1, reaction temperature 65℃, reaction time 3.0 h, and CSS/oil mass ratio of 2 wt%. After 7 consecutive reactions without any treatment, biodiesel yield reduced to 82.5%. Considering technological and economic feasibility, CSS base catalyst supported on θ rings was prepared for continuous transesterification. The maximum yield was 99.1% under optimum conditions (reaction temperature 55℃,methanol velocity 1 ml·min^-1, oil velocity 3ml·min^-1, and 5 tower sections). These results indicate that this newcontinuous biodiesel production process and apparatus present a great potential for industrial application in biodiesel.

Glycyrrhetic acid 3-O-mono-β-D-glucuronide (GAMG), the major functional ingredient in licorice, has widespread applications in food, pharmacy and cosmetics industry. The production of GAMG through Penicillium purpurogenum Li-3 cultivationwas for the first time performed through both batch and fed-batch processes in bioreactors. In batch process, under optimal conditions (pH 5.0, temperature 32℃, agitation speed 100 r·min^-1), 3.55 g·L^-1 GAMGwas obtained in a 2.5 L fermentor. To further enhance GAMG production, a fine fed-batch process was developed by using pH and DO as feedback parameters. Starting from 48 h, 100 ml 90 g·L^-1 substrate Glycyrrhizin (GL) was fed each time when pH increased to above 5.0 and DO was increased to above 80%. This strategy can significantly enhance GAMG production: the achieved GL conversion was 95.34% with GAMG yield of 95.15%, and GAMG concentration was 16.62 g·L^-1 which was 5 times higher than that of batch. Then, a two-step separation strategy was established to separate GAMG from fermentation broth by crude extraction of 15 ml column packed with D101 resin followed by fine purification with preparative C18 chromatography. The obtainedGAMG purity was 95.79%. This study provides a new insight into the industrial bioprocess of high-level GAMG production.

The glucose mass transfer in the biosynthesis of succinic acid with immobilized Actinobacillus succinogenes cells has been comparatively analyzed for a bioreactor with mobile bed vs. a stationary basket bioreactor. The process has been considered to occur under substrate and product inhibitory effects. The results indicated that the bioreactor withmobile bed is more efficient for biocatalyst particles with a diameter over 3mm,while the basket bioreactor ismore efficient for smaller biocatalyst particles and basket bed thickness below 5mm. The performances of both configurations of immobilized A. succinogenes cell beds were found to be superior to the column packed bed bioreactor.

Adsorption processes have received special attention for contaminants removal thanks to their capability to generate effluents with high quality as well as their simple design. In the current work, the agro-waste residue avocado peel is proposed to be used as alternative to conventional activated carbons whose use is sometimes restricted to high costs, upgraded by their exhausting after long term operations. The carbonization procedure was optimized and analyzed through factorial design and response surface methodology by evaluating temperature (400-900℃) and time (30-90 min) effects: optimal conditions were found at 900℃ and 65 min, generating an adsorbent with 87.52 m²·g^-1 of BET surface area, a mesopore volume of 74% and a zero point charge at 8.6. The feasibility of the carbonaceousmaterialwas proved for the removal of a variety of dyes by investigating substrate (10-50 mg·L^-1) and solid (0.5-20 g·L^-1) concentration effects and statistical significance: complete removal of Naphthol Blue Black and Reactive Black 5 was reached under optimal conditions (10 mg·L^-1 and 20 g·L^-1 of dye and solid, respectively),while Basic Blue 41was eliminated by using 13.4 g·L^-1 of the adsorbent. Overall, dyes removal by adsorption on carbonized avocado peel is presented as a promising technology due to the lowcost and easy availability of the precursor, aswell as the straightforward generation, the satisfactory characteristics and the proved adsorption capacity of the adsorbent.

An investigationwas performed on the suitability of carbonmaterials,metallic lead and its alloys as substrates for zinc negative electrode in acid PbO₂-Zn single flow batteries. The zinc deposition process was carried out in the medium of 1 mol·L^-1 H₂SO₄ at room temperature. No maximum current appears on the potentiostatic current transients for the zinc deposition on lead and its alloys.With increasing overpotential, the progressive nucleation turns to be a 3D-instantaneous nucleation process for the resin-graphite composite. Hydrogen evolution on the graphite composite is effectively suppressedwith the doping of a polymer resin. The hydrogen evolution reaction on the lead is relatively weak, while on the lead alloys, it becomes serious to a certain degree. Although the exchange current density of zinc deposition and dissolution process on the graphite composite is relatively low, the zinc corrosion is weakened to a great extent. With the increase of deposition time, zinc deposits are more compact. The cyclings of zinc galvanostatic charge-discharge on the graphite composite provide more than 90% of coulombic and 80% of energy efficiencies, and exhibit superior cycling stability during the first 10 cycles.

The aimof this study is to determine the effect of the main chemical components of biomass: cellulose, hemicellulose and lignin, on chemical kinetics of biomass pyrolysis. The experimentswere designed based on a simplexlattice mixture design. The pyrolysis was observed by using a thermogravimetric analyzer. The curves obtained from the employed analytical method fit the experimental data (R² > 0.9). This indicated that this method has the potential to determine the kinetic parameters such as the activation energy (E_a), frequency factor (A) and reaction order (n) for each point of the experimental design. The results obtained fromthe simplex-latticemixture design indicated that cellulose had a significant effect on E_a and A, and the interaction between cellulose and lignin had an important effect on the reaction order, n. The proposed models were then proved to be useful for predicting pyrolysis behavior in real biomass and so could be used as a simple approximation for predicting the overall trend of chemical reaction kinetics.

Two water soluble acryl terpolymers containing polyvinyl alcohol, acrylamide/acrylic acid and vinyl sulphonic acid (VSA) were synthesized by free radical polymerization in aqueous medium. The morphological structure of the polymers were analysed using FTIR and ¹H NMR, while the thermal properties were analysed by TGA and DSC. The inhibitive action of the terpolymers on corrosion of mid-steel in 1 mol·L^-1 HCl was studied using gravimetric, potentiodynamic polarisation and electrochemical impedance spectroscopy (EIS) at 303 K. Both the polymers provided inhibition efficiency around 90% which clearly demonstrate that the grafted polymers have effective corrosion inhibiting ability on MS corrosion.