Volume 20 (2018): Issue 3 (September 2018)

A spent vanadium catalyst, from the plant of metallurgical type, was leached in a potassium hydroxide solution to recover vanadium. The effect of time, temperature, concentration of basic, catalyst particle size and phase ratio was studied. The results showed that for a 160-750 μm catalyst leached for 4 h at 313.15 K in the presence of 10% potassium hydroxide solution at a liquid: solid ratio of 20:1, the extent of leaching of V was about 87%. Additionally, separation of vanadium from such a solution was investigated by the ion exchange method. Two types of polymer strongly basic ion exchangers were used. The ion exchange tests indicate that vanadium were loaded from the post-leaching solution with high effi ciency. On this basis a fl owsheet for the proposed process of a complex utilization of the spent vanadium catalyst is presented.

Catalytic cracking of volatiles derived from wet pig manure (WPM), dried pig manure and their compost was investigated over Ni/Al2O3 and Ni-loaded on lignite char (Ni/C). Non-catalytic pyrolysis of WPM resulted in a carbon conversion of 43.3% and 18.5% in heavy tar and light tar, respectively. No tar was formed when Ni/Al2O3 was introduced for WPM gasifi cation and the gas yield signifi cantly reached to a high value of 64.4 mmol/g at 650oC. When Ni/C was employed, 5.9% of carbon in the light tar was found at 650oC, revealing that the Ni/C is not active enough for cracking of tarry materials. The pyrolysis vapor was cracked completely and gave a H2-rich tar free syngas in high yield. High water amount of WPM promotes steam gasifi cation of char support, causing the deactivation of Ni/C. Such a study may be benefi cial to the development of livestock manure catalytic gasifi cation technology.

Yb³⁺/Er³⁺/GZO ceramics have been synthesized with high temperature solid-state method. The phase and structure of the Yb³⁺/Er³⁺/GZO ceramics were characterized by X-ray diffraction (XRD). The XRD pattern that following ions Yb³⁺, Er³⁺ and Ga³⁺ were well doped into the ZnO lattice. Effi cient visible up-conversion (UC) red and green emission were observed under 980 nm excitation. The mechanism of the UC luminescence is investigated on the basis of the UC luminescence emission spectra, the power curve and energy level diagram. The infl uence of doping ions to the intensity ratio of red to green is analyzed and high purity of red light (red/green = 29.9) is fi nally obtained.

Adsorption of Cu(II) and Ni(II) ions onto the waste powdered activated sludge biomass (PWB), which was obtained from the biological wastewater treatment plant, was investigated in this experimental study. The effects of contact time, pH, temperature, initial sorbate and sorbent concentrations on the adsorption were determined. The BET surface area, pore volume, and pore diameter of PWB were found to be about 0.51 m2/g, 0.0053 cm3/g, and 41.4 nm, respectively. Considering the R2 value, qexp and qcal, the Langmuir and Freundlich models were well described for Cu(II) and Ni(II) adsorption, respectively. The adsorption mechanism of Cu(II) and Ni(II) onto the PWB could be better simulated by the pseudo-second-order kinetic mechanism than the pseudo-fi rst-order, intra particle diffusion and Elovich models. Thermodynamic aspects of the adsorption of heavy metals were also investigated. Considering the applied desorbing agents for reuse of PWB for Ni(II) recovery, desorption cycle is not feasible due to the deterioration of the PWB structure.

A novel effi cient adsorbent, alkali-pretreated Paeonia ostii seed coats (AP-PSC), was investigated for the removal of methylene blue (MB) dye from solution. Orthogonal array design was applied to optimize the process parameters viz. alkali concentration, liquid-solid ratio (LSR) and pretreatment time. The results revealed that the optimal pretreatment conditions were at 0.8% (w/w) NaOH with LSR of 0.35 L g-1 treating for 50 min. Equilibrium and kinetic studies indicated that Langmuir isotherm and Pseudo-second-order models described the experimental data well. The maximum adsorption capability was of 368.2 mg g-1 for MB at 25oC. Thermodynamic parameters suggested that the AP-PSC adsorption process was physical, endothermic and spontaneous. Furthermore, the adsorption process was infl uenced by several interactive mechanisms, including ion-exchange, as well as Van der Waals forces and hydrogen bonds that occur concomitantly. It was concluded that AP-PSC may be potential as an effi cient adsorbent to remove MB from solution.

N,N-dihydroxybenzene-1,3-dicarboximidoyl dichloride was synthesized from benzene-1,3-dicarboxaldehyde and characterized by fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (1H and 13C NMR). The elastomer was prepared through the 1,3-dipolar cycloaddition of reaction between liquid polybutadiene (LPB) and isophthalonitrile oxide in this work. The tensile strength of different elastomer was enhanced from 0.14 MPa to 0.33 MPa as the elongation at break decreased from 145% to 73%, and the modulus increased from 0.09 kPa to 0.47 kPa. The parameters of kinetic indicated that the curing reaction was fi rst order reaction and the apparent activation energy of each curing system was less than 10.10 kJ/mol when the content of N,N-dihydroxybenzene-1,3- dicarboximidoyl dichloride was increased from 7% to 12%. These results suggested that nitrile oxides achieved curing of polymer binders at room temperature and this work had defi nite guiding signifi cance for the application of nitrile oxides in polymer binders.

The adsorption of pentafl uorobenzene on nine ionic liquid-based silicas was investigated using solid phase extraction. The effects of several variables such as the type of ionic liquid groups, adsorption time, temperatures and water ratio in the solution system were experimentally evaluated. The imidazole-chloride ionic liquid group based silica exhibited the highest adsorption effi ciency under the optimized conditions of 5 min adsorption at 30oC in water/methanol (30:70, vol%) solution. In addition, the effects of pH, as well as type and concentrations of chloride salts were investigated. At pH values other than neutral and high salt concentration, the adsorption effi ciency was reduced. Finally, the relative standard deviation of less than 5.8% over a 5-day period showed a high precision for the nine tested sorbents.

The course of epoxidation of sesame oil (SO) with performic acid formed „in situ” by the reaction of 30 wt% hydrogen peroxide and formic acid in the presence of sulfuric acid(VI) as a catalyst was studied. The most advantageous of the technological independent parameters of epoxidation are as follows: temperature 80°C, H2O2/ C=C 3.5:1, HCOOH/C=C 0.8:1, amount of catalyst as H2SO4/(H2O2+HCOOH) 1 wt%, stirring speed at least 700 rpm, reaction time 6 h. The iodine number (IN), epoxy number (EN), a relative conversion to oxirane (RCO) and oxirane oxygen content (EOe) were determined every hour during the reaction. Under optimal conditions the sesame oil conversion amounted to 90.7%, the selectivity of transformation to epoxidized sesame oil was equal to 93.2%, EN = 0.34 mol/100 g, IN = 0.04 mol/100 g oil (10.2 g/100 g oil), a relative conversion to oxirane RCO = 84.6%, and oxirane oxygen content of EOe = 5.5%.

Polyethylene oxo-degradable composites containing antibacterial substances in the form of vegetable oils: geranium, clove and eucalyptus as well as a mixture of nanoAg with nanoCu were discussed. Antibacterial fi lm: PE-0, PE- 1A, PE-2B, PE-3C, PE-4D properties were verifi ed according to ISO 22196:2011 “Measurement of antibacterial activity on plastic and other non-porous surfaces” for the two standard bacteria species of E. coli and S. aureus, whereas water vapour permeability tests (Pv) were carried out acc. ISO 15106-2007 “Plastics. Foils and plates. Determination of water vapor transmission rate. Part 1: Humidity sensor method”. Film marked PE-4D showed the best antibacterial features and good barrier properties.

The membrane distillation performance was studied for production of demineralized water from surface water (river). Hot water from cooling water system of municipal waste incinerator was considered as an energy source for membrane distillation. The integration of membrane installation with such cooling water system allows to re-use up to 18 kW per 1 m2 of the membranes. The studies were performed with the application of polypropylene capillary membranes Accurel PP S6/2. The membrane modules were supplied with the feed heated to a temperature of 310 K and 330 K. The permeate fl ux obtained for these temperatures was 2.8 and 9.7 L/m2 h, and the distillate conductivity was 6 and 4 S/cm, respectively. The water demineralisation process was carried out for 1200 h without module cleaning. The behaviour of the permeate fl ux and distillate conductivity indicate that used membranes maintained their non-wettability over tested period. The performed SEM-EDS examinations confi rmed, that the deposits did not fi ll the pores and were mainly formed on the membrane surface. The scaling intensity was defi nitely smaller for lower temperature (310 K) of the feed. The amorphous deposits containing beside Ca also substantial amounts of the Si were mainly formed under these conditions, whereas at higher feed temperature dominated CaCO3 scaling.

In this work for the fi rst time, activated carbons were prepared from carboxymethyl fi lm (low-cost carboxymethyl fi lm waste), using chemical activation with potassium hydroxide. The samples were characterized by nitrogen adsorption-desorption at 77 K, XRD, SEM methods. The high values of the specifi c surface area and total pore volume were achieved and were equal to 2064 m2/g and 1.188 cm3/g, respectively. Waste from the fi lm can be immediately utilized without CO2 production. This is the environmentally friendly way of waste utilization. Through this process, we can protect our environment. This study showed that the activated carbon obtained from carboxymethyl fi lm waste can be used as a good adsorbent for CO2 adsorption.

The aim of this work was to develop the method of lactic acid (LA) separation from fermented whey. CMI-7000 Cation Exchange Membrane and AMI-7001 Anion Exchange Membrane were employed in electrodialysis process. Experiments showed that the selected membranes separated organic acids effectively (including LA) from other organic ingredients present in medium. Selecting an appropriate volume of a receiving chamber could lead to LA concentration. Moreover, membrane fouling during separation was investigated. This phenomenon is negligible which is the main advantage of this process. As it was shown during batch processes, with the voltage increase, the rate of electrodialysis increases as well. It prompts to a reduction of residence time in electrodialyzer during a continuous separation.

Secondary activation of commercial activated carbon (AC) ORGANOSORB 10-CO was carried out at 600, 700 and 800oC with mass ratios of potassium to AC (K/AC) in range 1-3. Crucial samples have shown following CO2 uptakes and SSA - 3.90 mmol/g and 1225 m2/g, 4.54 mmol/g and 1546 m2/g, 4.28 and 1717 m2/g for pristine material and samples obtained at 700oC with K/AC = 2 and at 800oC with K/AC = 3 respectively. Last sample also indicated signifi cant mesopore volume increase in diameter range 2-5 nm, from 0.11 to 0.24 cm3/g. CO2 uptake increase was explained by formation of micropores up to diameter of 0.8 nm, which distribution was established from CO2 sorption using DFT. Surface chemistry of all samples has not changed during modifi cation, what was proven by XPS. Moreover, deeper incorporation of potassium ions into graphite at higher temperatures was observed as confi rmed with EDS, XPS and XRD.

Soybean curd is a very popular food containing high-quality protein, polyunsaturated fats, vitamins, minerals and other nutrients. This study aims to prepare porous soybean curd xerogels via a vacuum freeze drying method and uses them as adsorbents to remove congo red from aqueous solutions. The morphology and functional groups of the soybean curd xerogels were characterized using scanning electron microscopy and Fourier transform infrared spectroscopy, respectively. The adsorption properties of congo red onto the soybean curd xerogels were carried out through investigating the infl uencing experimental parameters such as the drying method, solution pH, adsorbent dose, contact time and temperature. The results showed that the adsorption isotherm data were fitted well to the Freundlich isotherm. Adsorption kinetics of congo red onto the soybean curd followed the pseudo-second-order kinetic model. The thermodynamic parameters, such as ΔG0, ΔH0 and ΔS0, were also determined.

Desulfurization of Pakistani coal has been carried out through alkaline leaching. During present experimental investigation, the effect of operating parameters like alkali concentration, time, temperature and particle size has also been analyzed, graphically represented and critically discussed. Parametric optimization of leaching process has been carried out by using response surface methodology (RSM) based on central composite design (CCD). The analysis of variance (ANOVA) was performed in order to assess the highest level interactions of variables and three way interactions were observed signifi cant. Further, the optimum value of total sulfur removal was observed as 53% when the operatic conditions fi xed at 10% W/V, 60 min, 80oC and 140 mesh for alkaline concentration, leaching time, temperature and particle size, respectively.