Recent Innovations in Chemical Engineering (Formerly Recent Patents on Chemical Engineering) - Volume 11, Issue 1, 2018

Background: Improved mycelial pellet with superior decolorization ability and reusability was firstly cultivated and coupled with activated carbon for enhancement of dyecontaining wastewater adsorption, which was named MP-AC. Methodology: Depending on several parameters such as pellet size and dry/wet ratio, the optimum amount of activated carbon powder was determined as 0.015 g·mL-1 spore suspension, and the mycelial pellet contained the certain amount of activated carbon powder named as MP-AC-5. The microscope and SEM images clearly described the activated carbon powder wrapped in the net of pellet unevenly without destroying the structure. By comparing with single mycelial pellets (SMP) under different condition, the decolorization ability of MP-AC-5 was investigated and the results showed that MP-AC-5 (1.0g) had higher decolorization efficiency and better reusability than SMP (1.5g) under different pH and dyeconcentrations. Conclusion: The pseudo-second order kinetic model was able to describe the biosorption equilibrium of Eriochrome black T (EBT) onto the MP-AC-5 with a high determination coefficient (R2 > 0.999) and the Langmuir isotherm model was able to describe the biosorption equilibrium of Eriochrome black T (EBT) onto the MP-AC-5.

Background: Fenton reaction has been used for wastewater treatment. Photo- Fenton-like reaction which utilizes light irradiation is an alternative for Fenton reaction to enhance the degradation of pollutants. Objective: To synthesize a photo-Fenton-like catalyst of high catalytic activity. Methods: The heterojunction photo-Fenton-like catalysts of Cu2S-TiO2/multi-walled carbon nanotubes (MWCNTs) were prepared by incorporating photocatalyst TiO2 into Fenton-like catalyst Cu2S-loaded MWCNTs (Cu2S/MWCNTs). The morphologies and structures of the samples were studied by means of transmission electron microscopy (TEM), X-ray diffraction (XRD), and nitrogen adsorption/desorption at 77 K. The photo-Fenton-like catalytic activity of TiO2-Cu2S/MWCNTs was investigated with degradation of methylene blue under solar light. Results: TiO2-Cu2S/MWCNTs nanocomposites were prepared by incorporating TiO2 into Cu2S/MWCNTs. The XRD results showed the coexistence of anatase TiO2 and Cu2S in the samples. The nanocomposites had a nanoporous structure with BET specific surface area of 105 m2g-1 and main mesopores with pore volume of 0.71 cm3g-1, showing photo-Fenton-like catalytic efficiency much higher than only Cu2S/MWCNTs under solar light. Conclusion: The novel Cu2S-TiO2/MWCNTs exhibited high photo-Fenton-like catalytic efficiency under solar light. It could be explored as a catalyst for wastewater treatment.

Background: The research works on circulating fluidized bed are mostly devoted to investigation of the process in separate parts of a circulating fluidized bed reactor, and practically never to investigation of the entire circulating loop. The interference between the processes in the riser, separator and downer remains practically unexamined. Objective: The objective of the study is to develop a simple yet informative model to investigate the features of a particulate flows forming in a circulating gas-solid fluidized bed reactor. Method: The method of mathematical modeling is used. The proposed model is based on the theory of Markov chains. The transformation of a raw particulate material into an end product in the riser is taken into account. The return flow in a downer is described with a time delay between the inflow and outflow from it. Results: The proposed model allowed performing numerical experiments on the influence of the process parameters on its main technological characteristics both for the transient and steady state. Conclusion: It is found that the batch circulating fluidization has advantages in comparison to the dense bed only at a small time delay in the downer and a relatively high gas flow velocity in the riser. It is also found that the maximum feed flow rate exists in a continuous circulating fluidization that ensures the stable operation of the circuit. This threshold crossing leads to the overfilling of the riser and its blockage. Optimal positioning of the return flow input allows increasing this maximum feed flow rate.

Purpose: The purpose of this preliminary study is to investigate the capability of Graphene Oxide (GO) coated Quartz Crystal Microbalance (QCM) sensor for the detection of cancerous related volatile organic compounds (VOCs). Methodology: The detection of selected six polar and two non-polar VOCs is mainly based on the selectivity and sensitivity of the graphene oxide (GO) films in parts per million (ppm) concentrations. The GO solutions with different concentrations (0.1, 0.5 and 1.0 mg/ml) were coated using the drop coating technique on the both sides of QCM surfaces. These experiments were conducted to study the effect of different GO concentration. An experimental setup was prepared to measure the frequency changes (Δf) of QCM when the sensors were exposed to the synthetic VOCs. In addition, the adsorption characteristic of GO on each odour sample was explained in detail. The surface modifications of QCM with GO film were studied using Field Emission Scanning Electron Microscopy (FESEM). Findings: The results showed that the QCM coated with 1mg/ml was able to respond to minimum concentration of 0.5ppm VOCs. The sensitivity of QCM sensor was observed to be linearly correlated with the (VOCs) concentration given in part per million (ppm). The results demonstrate that the GO coated QCM exhibits high sensitivity and selectivity towards alcohol based vapours. The exposure of each vapour was observed to give different response value. The patterns of the vapour responses were different according to the functional groups. The sensor was also observed to deliver a consistent response under several repetitions. The sensor also exhibited rapid response-recovery performance. Thus, this formulation of GOcoated QCM shows high potential to be a non-invasive cancer screening tool. Originality: This initial study, a low-cost and reproducible GO-QCM based to detect cancerrelated VOCs was investigated. The high sensitivity to polar VOCs and good selectivity information can be referred to classify the cancer types accordingly.

Objective and Method: In this paper, dye is used as pH sensors. We here report the study of the effect of pH solutions on Methyl red doped polystyrene and Bromocresol Purple doped Styrene acrylonitrile waveguides. The effect of pH solutions was observed on the absorption spectra and output intensity of the waveguides. Conclusion: It was observed that for pH solutions to which the dye is sensitive, output intensity decreased and it was clearly seen in absorption spectra too. Methyl red doped polystyrene waveguides showed sensitivity for pH range 5-6 and Bromocresol purple doped Styrene acrylonitrile waveguides showed sensitivity for pH range 5-9. These dye-doped polymer waveguides can be used as pH sensors.

Background: TiO2 photocatalyst is promising for wastewater treatment, but it is still restricted under visible light. Objective: To prepare TiO2 based-photocatalyst of good performance under visible light. Methods: By doping manganese (Mn) and using multi-walled carbon nanotubes (MWCNTs) as a substrate, we prepared carbon nanotube-supported Mn-TiO2 (Mn-TiO2/MWCNTs) nano-composites with a solvothermal-annealing method. The samples were characterized by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The photocatalytic activity of Mn-TiO2/MWCNTs was investigated by the degradation of methylene blue (MB) under visible light. Results: It was found that Mn-TiO2 nanoparticles were loaded uniformly on the MWCNTs. Mn-TiO2/MWCNTs showed higher photocatalytic efficiency than pure TiO2 and Mn-TiO2. Only 47.0% of MB was degraded by TiO2 and 67.2% of MB was degraded by Mn-TiO2, while 80.0% of MB was degraded by Mn-TiO2/MWCNTs in 80 minutes. Conclusion: Because the Mn doping reduced the energy gap of TiO2 and inhibited the recombination of photogenerated electron-hole pairs and because the large suface area and good electro-conductivity of MWCNTs enhanced the photocatalytic efficiency of TiO2, Mn- TiO2/MWCNTs showed an enhanced catalytic performance under visible light.

Background: A study was conducted to investigate the effects of activation by CO2, steam and their sequential combinations on the development of pores of activated carbon derived from ZnCl2-treated oil palm kernel shell. Results & Conclusion: The results show that the combination of CO2 and steam, regardless of their sequence, results in a higher carbon burn-off than the single activating agents. The combination of activation in the sequence of CO2-steam, however, gives the highest value of carbon burn-off and produces activated carbon with the highest total pore volume and BET surface area. Steam activation favours the creation of new microporous structures, while CO2 activation tends to widen existing pores leading to the formation of mesoporous structures. The preferential action of different activating agents can be related to the size of their molecules and the rate at which they dissociate and react with carbon.

Background: Gasification is a popular process for producing syngas from solid fuels. The focus has nowadays shifted to co-gasification using a mixed feed of coal and biomass. An optimum gasifier operating condition (OGOC) is an extremely important process parameter for gasification system. Method: A thermodynamic analysis was done to calculate this condition for co-gasifier operation. The relative product gas generation trends in co-gasification were compared with the single feed coal gasification in this study. Conclusion: An OGOC of 618°C with CO2 feed of 0.6475 moles and H2O feed of 1.3525 moles was found to be the best condition for co-gasifier operation producing 1.6429 moles of syngas (of syngas ratio 1.5905) and 54.96% H2O conversion with the gasifier product gas containing over 61% syngas. Such OGOC can be found for gasification systems ensuring the advantages of thermoneutral operation as well as 100% carbon conversion.