Microwave-assisted hydrothermal carbonization of rice husk and rice straw for its applications as a solid fuel and a filler for polymer composites

Biomass utilization has received much attention for production of high-density solid fuels. Utilization of cheap and naturally available precursors through environmentally friendly and effective processes is an attractive and emerging research area. Pyrolysis and hydrothermal carbonization (HTC) are well-known technologies available for production of solid biofuel using conventional or microwave heating. Microwave heating is a simpler and more efficient heating method than conventional heating. The process parameters of microwave hydrothermal carbonization (MHTC) have significant effect on yield of hydrochar. For the first time, this study discusses the effect of process parameters including reaction temperature, reaction time, particle size and biomass to water ratio on hydrochar yield produced from MHTC of rice husk and rice straw. Further, both the feed material and hydrochars have been characterized for energy, chemical, structural and thermal properties. Results revealed that, over the ranges tested, a lower temperature, lower reaction time, lower biomass to water ratio and higher particle size produce more hydrochar. The higher heating value (HHV) was improved significantly from 16.46 MJ/kg and 12.3 MJ/kg of rice husk and rice straw to 24.89 MJ/kg and 17.6MJ/kg of rice husk hydrochar and rice straw hydrochar, respectively. Elemental analysis results of rice husk and its hydrochar show that the carbon content increased, and oxygen content decreased in hydrochar from 25.9 to 44.9% and 68.5 to 47.0%. On the other hand, the carbon content and fixed carbon values were increased from 37.19% and 14.37% for rice straw to 48.8% and 35.4% for rice straw hydrochar. SEM analysis exhibited modification in structure of rice husk and improvement in porosity after MHTC, which was further confirmed from BET surface analysis. The BET surface area increased from 25.0656 m2/g (rice husk) to 92.6832 m2/g (hydrochar). Thermal stability of hydrochar was improved from 340 oC for rice husk to 370 oC for hydrochar. A polymer composite is fabricated by incorporating fillers into a polymer matrix at different concentrations. The addition of fillers helps to improve the physical, mechanical, chemical and thermal properties of the composite. This study utilizes hydrochar for the first time, synthesised by microwave-assisted hydrothermal carbonization of rice husk and rice straw, as filler for polylactide/hydrochar composites. The polylactide/hydrochar composites were fabricated by incorporating hydrochar in polylactide at 5%, 10%, 15% and 20 wt% by melt processing in a Haake rheomix at 170 ºC. Both the neat polylactide and polylactide/hydrochar composites were characterized for mechanical, structural, thermal and rheological properties. The tensile modulus of polylactide/hydrochar composites was improved from 2.63 GPa (neat polylactide) to 3.16 GPa, 3.33 GPa, 3.54 GPa, and 4.24 GPa after blending with hydrochar at 5%, 10%, 15%, and 20%, respectively. Further, the incorporation of hydrochar had little effect on storage modulus (G') and loss modulus (G"). The findings of this study suggest that addition of hydrochar improves the overall characteristics of polylactide composites confirming the suitability of hydrochar as filler for polymer/hydrochar composites

Studies on wear resistance of PTFE filled with glass and bronze particles based on Taguchi technique

An attempt has been made to study the influence of wear parameters like applied load, sliding speed, sliding distance on the dry sliding wear of polytetrafluroethylene (PTFE), PTFE + 25% glass and PTFE + 40% bronze composites. Experiments, based on the techniques of Taguchi, were performed to acquire data in a controlled way. An orthogonal array and the analysis of variance were employed to investigate the influence of process parameters on the wear of composites. The worn surfaces were examined using scanning electron microscope (SEM). The experimental results show that sliding distance and applied load were found to be the more significant factors among the other control factors on wear. The objective is to establish a correlation between dry sliding wear of composites and wear parameters. These correlations were obtained by multiple regressions. A good agreement between the predicted and actual wear resistance was seen

Synthesis and characterization of rice husk biochar via hydrothermal carbonization for wastewater treatment and biofuel production.

The recent implication of circular economy in Australia spurred the demand for waste material utilization for value-added product generations on a commercial scale. Therefore, this experimental study emphasized on agricultural waste biomass, rice husk (RH) as potential feedstock to produce valuable products. Rice husk biochar (RB) was obtained at temperature: 180 °C, pressure: 70 bar, reaction time: 20 min with water via hydrothermal carbonization (HTC), and the obtained biochar yield was 57.9%. Enhancement of zeta potential value from - 30.1 to - 10.6 mV in RB presented the higher suspension stability, and improvement of surface area and porosity in RB demonstrated the wastewater adsorption capacity. Along with that, an increase of crystallinity in RB, 60.5%, also indicates the enhancement of the catalytic performance of the material significantly more favorable to improve the adsorption efficiency of transitional compounds. In contrast, an increase of the atomic O/C ratio in RB, 0.51 delineated high breakdown of the cellulosic component, which is favorable for biofuel purpose. 13.98% SiO2 reduction in RB confirmed ash content minimization and better quality of fuel properties. Therefore, the rice husk biochar through HTC can be considered a suitable material for further application to treat wastewater and generate bioenergy

Microwave Hydrothermal Carbonization of Rice Straw: Optimization of Process Parameters and Upgrading of Chemical, Fuel, Structural and Thermal Properties.

The process parameters of microwave-induced hydrothermal carbonization (MIHTC) play an important role on the hydrothermal chars (hydrochar) yield. The effect of reaction temperature, reaction time, particle size and biomass to water ratio was optimized for hydrochar yield by modeling using the central composite design (CCD). Further, the rice straw and hydrochar at optimum conditions have been characterized for energy, chemical, structural and thermal properties. The optimum condition for hydrochar synthesis was found to be at a 180 °C reaction temperature, a 20 min reaction time, a 1:15 weight per volume (w/v) biomass to water ratio and a 3 mm particle size, yielding 57.9% of hydrochar. The higher heating value (HHV), carbon content and fixed carbon values increased from 12.3 MJ/kg, 37.19% and 14.37% for rice straw to 17.6 MJ/kg, 48.8% and 35.4% for hydrochar. The porosity, crystallinity and thermal stability of the hydrochar were improved remarkably compared to rice straw after MIHTC. Two characteristic peaks from XRD were observed at 2? of 15° and 26°, whereas DTG peaks were observed at 50?150 °C and 300?350 °C for both the materials. Based on the results, it can be suggested that the hydrochar could be potentially used for adsorption, carbon sequestration, energy and agriculture applications

Designing EthAKUL: A mobile just-in-time learning environment for bioethics in Pakistan

In developing countries such as Pakistan, bioethics has not been included in mainstream thinking in medical education. The authors’ experiences suggest that current methods of teaching bioethics are problematic as students are unable to translate theory to practice. Alternative pedagogies, such as just-in-time learning (JiTL) using mobile devices, may be able to foster the development and implementation of ethical reasoning among nurses, doctors, and medical and nursing students. This research was conceived to determine the effectiveness of mobile JiTL – anytime, anyplace learning through mobile devices – for teaching bioethics. After obtaining ethical clearance, a participatory design (PD) approach was adopted to ensure input from all stakeholders for the design of ‘EthAKUL’, comprising a mobile app, five modules and just-in-time pedagogy. The name of the app is an acronym evoking ethics, learning and the university where the project originated. As a part of the design process, three PD workshops were held with junior doctors, nurses, nursing students, medical students and bioethics teaching faculty, and five meetings were held with faculty members, to discuss functional specifications and user-acceptance testing of the app. The feedback related to the nature of common ethical issues encountered in clinical settings, the existing process of teaching and learning bioethics, and the requested features of the app were recorded. These data sets were analyzed and synthesized into functional and technical specifications for the mobile app. The software programmers developed the app with the close involvement of the stakeholders. The development of teaching content continued alongside this process. While this enabled EthAKUL’s developers to incorporate needs of all stakeholders, challenges were encountered in the process relating to the pragmatic and conceptual aspects of JiTL, ML and PD. We discuss the implications of this research in bringing about transformative changes in higher education

Effects of two CIDR-based oestrus synchronization protocols on oestrus response in boer goats.

Sixty fertile and healthy female Boer goats were divided equally and randomly into two groups (n=30). The first group received CIDR treatment for 14 days (T14) with 400 IU PMSG and 0.05 mg cloprostenol injection (i.m.) prior to CIDR removal and the second group received CIDR treatment for 9 days (T9) with 0.05 mg cloprostenol injection (i.m.) 24 hours before CIDR removal. The number of does with oestrus and the time of oestrus sign were recorded every 6-hour interval and the observation was conducted from 24 hours after CIDR removal and terminated 66 hours after CIDR removal. Blood samples were taken from all of the does before CIDR insertion and 48 hours after CIDR removal. The results showed all 30 does (100%) in T14 and 28 does (93.3%) in T9 came to oestrus. The mean time of does showing signs of oestrus for both treatments were significantly different in tail flagging and standing to be mounted (P0.05). The current study suggests that CIDR treatment for 14 days with 400 IU PMSG and 0.05 mg cloprostenol prior to CIDR removal gave better result in oestrus synchronisation compared to CIDR treatment for 9 days with 0.05 mg cloprostenol given 24 hours before CIDR removal

IL10 variant g.5311A is associated with Visceral Leishmaniasis in Indian population

Background: Visceral Leishmaniasis (VL) is a multifactorial disease, where the host genetics play a significant role in determining the disease outcome. The immunological role of anti-inflammatory cytokine, Interleukin 10 (IL10), has been well-documented in parasite infections and considered as a key regulatory cytokine for VL. Although VL patients in India display high level of IL10 in blood serum, no genetic study has been conducted to assess the VL susceptibility/resistance. Therefore, the aim of this study is to investigate the role of IL10 variations in Indian VL; and to estimate the distribution of disease associated allele in diverse Indian populations. Methodology: All the exons and exon-intron boundaries of IL10 were sequenced in 184 VL patients along with 172 ethnically matched controls from VL endemic region of India. Result and Discussion: Our analysis revealed four variations; rs1518111 (2195 A>G, intron), rs1554286 (2607 C>T, intron), rs3024496 (4976 T>C, 3’ UTR) and rs3024498 (5311 A>G, 3’ UTR). Of these, a variant g.5311A is significantly associated with VL (χ2 = 18.87; p = 0.00001). In silico approaches have shown that a putative micro RNA binding site (miR-4321) is lost in rs3024498 mRNA. Further, analysis of the above four variations in 1138 individuals from 34 ethnic populations, representing different social and linguistic groups who are inhabited in different geographical regions of India, showed variable frequency. Interestingly, we have found, majority of the tribal populations have low frequency of VL (‘A’ of rs3024498); and high frequency of leprosy (‘T’ of rs1554286), and Behcet’s (‘A’ of rs1518111) associated alleles, whereas these were vice versa in castes. Our findings suggest that majority of tribal populations of India carry the protected/less severe allele against VL, while risk/more severe allele for leprosy and Behcet’s disease. This study has potential implications in counseling and management of VL and other infectious diseases

Multiwall carbon nanotube promising route for removal of chromium from wastewater via batch column mechanism

Water pollution regarding heavy metals issue keep lingering our days from time to time, and some problems even left unattended. The most crucial cause of this pollution is the industrial waste, especially waste water that had been released into the drainage system without being treated first. This activity had been done illegally and left a huge impact towards the environment also human. In this study multiwall carbon nanotubes (MWCNTs) are promising route for removal of chromium was investigated. Results revealed that the optimum conditions for highest removal (99.97%) of chromium are pH7,0.04g of MWCNTs dosage, and flowrate of 20.83 mL/s. Based on adsorption isotherm for this experiment, the amount of chromium adsorbed, qm calculated was 50.51 mg of chromium/gram of MWCNTs. From the results obtained, it had been proved that MWCNTs can be used as an effective adsorbent in chromium removal from aqueous solution due to high adsorption capacity

Immobilization of lipase enzyme carbon nanotubes via adsorption

Lipase is an enzyme used widely in many major industries. Immobilization of enzymes will help to enhance its sustainability as enzymes are more resistance to changes in environment and can be reused. This experiment examines effects the immobilization of lipase with adsorption technique through carbon nanotubes. The paper investigates the enzyme activity and efficiency of immobilized enzyme lipase by using assay solution. It also presents the effects of pH on immobilized enzyme and the characterization of the immobilized enzyme lipase with FTIR spectrum and FESEM technique. The results showed that there are as enzyme concentration increases, the enzymatic activity increases too. However, this lowers the immobilization efficiency due to saturation of binding pores on functionalized MWCNTs. Meanwhile, the optimum pH for maximum immobilization activity of enzyme lipase is at pH 6. Based on the characterization by FTIR spectrum and FESEM, it is confirmed by the presence of functional group in FTIR spectrography. On the other side, FESEM also confirms that immobilization of enzyme has occurred