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Synthesis of hybrid nanomaterials in the lab-scale frequently involves complex processing and often is not able to be adopted in the industry without major enhancements for its commercial production. This research is focused on a convenient route for the fabrication of chitosan-supported magnetically recoverable carbon bio-nanocomposites by functionalizing magnetic nanoparticles on chitosan and renewable carbon material using solvothermal carbonization co-precipitation (STCC). This process can be adopted in large-scale synthesis with minimum enhancements. The nanocomposites produced using STCC offered excellent features including porous and ultrafine nanostructure, stable mechanical, and chemical properties. From the analysis of variance (ANOVA), the temperature has been found to be the most influential factor for both magnetic nanocomposite and bio-oil yield. The highest porosity for nanocomposites was observed with water-based synthesis at 260 °C at 194.62 m2/g. However, water/ethanol (50:50) at 260 °C yielded 6.67% and 8.01% more bio-oil and having 5.35% and 3.49% higher heating value as compared to that of bio-oil produced using water and ethanol.

Crystallization is an experimental phenomenon that does not always depend on predicted data for efficient processing. It, therefore, becomes important to conduct experiments in the seeded or unseeded crystallization process to gain insight into the growth kinetic parameters. The knowledge of the process and kinetic parameters is proved useful in developing strategies for the optimal design of crystallizers and in control of crystal size distribution. A differential scanning calorimeter (DSC) was used to perform isothermal growth experiments for seeded crystallization, and the kinetics was evaluated using a de-supersaturation curve. In order to get the de-supersaturation curve, the DSC heat flow signal was used to measure and quantify the mass change of seeds during the crystal growth process as a function of time at a particular temperature. Experiments were performed at temperatures ranging from 10 to 40 °C in sealed DSC pans. The growth order g was calculated from the isothermal experiments at varying temperatures, and the mass growth rate coefficient Kg, linear growth rate coefficient kg, mass rate of crystal growth RG and activation energy Ea of benzoic acid in the ethanol–water binary solvent were estimated from growth order g. The kinetic parameters were compared with the data obtained using online measurement techniques and found to be in good agreement. The present work establishes the reliability of calorimetric transformation studies for estimating growth kinetics using a small amount of sample in a very short period, at higher temperatures and pressures.

The objective of this study is the applications of hybrid magnetic nanocomposites as catalyst as well as an adsorbent. Four magnetic nanocomposites (graphene and chitosan based) were fabricated using single pot solvothermal carbonization co-precipitation (STCC) route by integrating biomass functionalized with iron oxide nanoparticles. All hybrid nanocomposites were characterized for their magnetic, thermal, chemical and structural properties. Adsorption isotherms and kinetics studies were performed for adsorption of multi-heavy metals including Cd, Ni, Cu and Cr. Finally, the hybrid magnetic carbon nanocomposites were tested as catalysts to produce bio-oil through catalytic liquefaction of rice husk in supercritical ethanol. It was found that the bio-oil yield and overall conversion was enhanced significantly from 29.5% and 48.11% without catalyst, to 36.8% and 60.81% respectively with the presence of magnetic carbon nanocomposites as catalyst. Furthermore, the bio-oil energy quality was enhanced in energy content from 21.72 to 23.21 MJ/kg with the presence of catalyst and H/C and O/C ratios were reduced. Finally, GCMS revealed that the bio-oil produced using catalysts showed higher mass fraction of esters, hydrocarbons and reduced acid groups as compared to bio-oil. This study provides insights to the understanding of the role of hybrid magnetic nanocomposites for its expansion for future applications.

This study aims to investigate the role of water and ethanol in ethanol/water mixed solvent system, co-liquefaction of high-density polyethylene (HDPE) and sugarcane bagasse (SCB) to produce high quality bio-oil. It was revealed that various ethanol/water mixing ratios led to various reaction mechanisms, which indicates that there is a clear synergy effect between water and ethanol liquefaction process in three reaction media. The conversion and bio-oil yield approach were in the order of pure water

Chabazite-K was synthesized from coal fly ash by a two-stage hydrothermal process. Fly ash was fused with KOH and colloidal SiO2, and the resulting material was characterized by x-ray diffraction (XRD) analysis and Raman spectroscopy. The role of KOH in the nucleation of chabazite is explained in terms of uniform incorporation of Al and Si tetrahedra in aluminosilicate rings at the fusion stage. Cocrystallization of phillipsite with chabazite led to the formation of phillipsite–chabazite combined phase along with chabazite-K. The Cs+ sorption capacity of the material was found to be 299 ± 8 mg/g with selectivity for Cs+. Under the same experimental conditions, fusion of fly ash in NaOH led to formation of sodalite, which can be explained in terms of preferential incorporation of Al tetrahedra in aluminosilicate rings at the fusion stage of synthesis.

It is now well documented that mercury is extremely toxic to both humans and the environment. A close-packed gold nanorod (Au-NR) monolayer was deposited on a titanium-based quartz crystal microbalance (QCM) and its performance for elemental mercury (Hg0) vapor sorption and detection was compared with that of a typical gold thin film (Au CTRL) based QCM device. The developed Au-NR based Hg0 sensor showed an up to ∼1.7 times higher response magnitude than its Au CTRL counterpart when exposed to Hg0 vapor concentrations of 0.21 to 3.26 mg m−3 at two different operating temperatures of 30 and 75 °C. The repeatability of the Au-NR sensor was calculated to be >90% when exposed to a series of sorption/desorption events with a Hg0 vapor concentration of 3.26 mg m−3. The calibration curves (i.e. response magnitudes vs. Hg0 concentrations) of the Au-NR sensor were found to follow the Langmuir extension isotherm, indicating the sensor's suitability to detect relatively low concentrations (ppb levels) of Hg0 vapor. Furthermore, the newly developed Au-NR sensor showed good selectivity (∼97%) toward Hg0 vapor when acetaldehyde co-existed in the gas mix. However, the selectivity of the sensor decreased to 66% and 67% when Hg0 vapor was detected in the presence of ammonia and water vapor, respectively. The selectivity data from the tested sensors were analysed to understand the selectivity performance of Au NRs toward Hg0 vapor in the presence of different gas species in order to implement improvements in developing the sensor for real world applications.

This study aims to investigate the co-liquefaction of high-density polyethylene (PE) and low density polyethylene bags (PB) with sugarcane bagasse (SCB) in supercritical ethanol solvent. The effect of blending ratios of SCB/PB and SCB/PE is studied. Results indicate that blending ratio of low density plastic bags and high-density polyethylene impacts the product distribution during solvo-thermal process. The optimum conversion of SCB/PE and SCB/PB up to 57.3% and 59.4% with bio-oil yields of 31.5% and 30.3% respectively are obtained at 280 °C. The higher heating values (HHV) of bio-oil obtained from SCB/PE and SCB/PB are 34.9 and 34.8 MJ/kg, respectively. CHNS/O, chemical composition, carbon and proton NMR, Thermogravimetric analysis (TGA) and Fourier-transform infrared spectroscopy (FTIR) analyses of bio-oil have been conducted. Investigation suggests that the SCB/PE and SCB/PB derived bio-oil have the superior qualitative properties compared to pure sugarcane bagasse.

A crosslinked poly(ionic liquid), with over 200% saturation capacity for iodine uptake from aqueous solutions and the vapour phase, has been prepared by crosslinking co-polymerisation of the ionic liquid monomer 1-butyl-3-vinylimidazolium bromide, and its utility in iodine immobilisation is demonstrated.

Role of composition and the nature of crosslinking on the properties of titania-chitosan beads have been investigated in detail. The investigations were done in order to explore the feasibility of design and synthesis of titania-chitosan beads with bespoke functionality based on the intended application. This would greatly enhance the potential for the industrial application of these biopolymer based beads. Beads of varying compositions (of titania and chitosan) were prepared and crosslinked using epichlorohydrin or glutaraldehyde. The physical characteristics and antimony binding properties of the resultant crosslinked titania-chitosan beads were investigated in detail. Influence of chitosan amount on swelling was seen to be more predominant in the glutaraldehyde crosslinked beads (TA-Cts-Glu). TA-Cts-Glu beads showed more swelling and better antimony (Sb(III) and Sb(V)) uptake as compared to the epichlorohydrin crosslinked beads (TA-CTS-Epi). While TA-Cts-Glu beads showed faster uptake kinetics compared to the TA-CTS-Epi beads, the latter showed selectivity towards Sb(III) against transition metal cations. Further, the beads exhibited differential uptake of Sb(V) and Sb(III). TA-Cts-Glu beads prepared with equal amounts of titania and chitosan showed the maximum Sb(V) uptake while the TA-Cts-Epi beads with higher chitosan to titania ratio showed the least. Sb(V) binding was enhanced by the crosslinked chitosan, while the Sb(III) uptake was aided predominantly by the titania content in the beads.

This article aims investigating the solvo and hydrothermal liquefaction of sugarcane bagasse. Reaction temperature and solvents play an important role on the yield and physico-chemical properties of the liquefaction products. This study reports the effect of different temperatures, 240 °C, 260 °C and 280 °C and two different solvents, water and ethanol on yield and properties of bio-oil and char. The higher conversion was obtained at the higher temperatures with ethanol. The bio-oil yield ranged from 46.0% to 51.8% in presence of water and it ranged from 54.6% to 62.3% with ethanol solvent by changing reaction temperature from 240 °C to 280 °C. The char yield decreased from 36.3% to 28.2% and from 39.3% to 24.7% in presence of water and ethanol respectively by varying reaction temperature from 240 °C to 280 °C. The carbon content and HHV were increased and oxygen content was decreased in the products resulting in improved heating and combustion performance. The GC–MS results suggested that the all the bio-oils were mainly composed of phenols and its derivatives, alcohols, esters, hydrocarbons, ketones, aldehydes and other compounds. The TGA results proposed that the thermal stability of char was improved which is attributed to the reaction temperature of the liquefaction process.

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. This study presents a critical review on microwave pyrolysis and microwave HTC for solid fuel production in terms of yield and quality of products. Moreover, a brief summary of parameters of microwave pyrolysis and microwave HTC are discussed. The fuel, chemical, structural and thermal weight loss characteristics of solid fuels produced from different biomass are discussed and compared.

The solubility of para-methoxyphenylacetic acid in different solvents is of critical significance for the design and optimization of its purification process via crystallization. The present study illustrates new solid–liquid phase equilibrium data of para-methoxy phenyl acetic acid in water, acetonitrile, propan-2-ol, morpholine, toluene, anisole, and binary (propan-2-ol + water, propan-2-ol + toluene) mixed solvents using a static analytical method from 283.15 to 323.15 K at atmospheric pressure. The highest solubility of para-methoxyphenylacetic acid was observed in propan-2-ol and lowest in water, with the maximum solubility effect for propan-2-ol + toluene binary system obtained at 0.5001 solute-free mole fraction of propan-2-ol. The modified Apelblat equation, λh (Buchowski) equation, and nonrandom two-liquid (NRTL) activity coefficient model were used to correlate the experimental solubility data in pure solvents, whereas the binary solvent systems were modeled using the van’t Hoff–Jouyban–Acree, A...

Pyrolysis and liquefaction are widely accepted methods used for the synthesis of bio-oil using biomass. The quality and quantity of the bio-oil, produced either from pyrolysis or liquefaction, depend on various parameters including reaction temperature, reaction time, type of solvent and its ratio to biomass, lignocellulosic composition of feedstock and catalyst. Comparatively, hydrothermal liquefaction (HTL) is considered as more economic and environmental friendly process than pyrolysis. For instance, pyrolysis emits volatile matter and requires a dry feedstock while HTL can handle both dry and wet biomass, hence, saving costs, energy and time required for drying the biomass. The bio-oil cannot be used directly for transportation and ignition purposes. Therefore, it needs an upgrading process to improve its physico-chemical properties. There are various methods for upgrading of bio-oil such as hydro-treatment, catalytic cracking, supercritical fluid (SCFs), esterification and emulsification. This review describes the HTL process for biomass and its important parameters in detail, and various techniques employed for upgrading of bio-oil. The review also summarizes the effect of biomass feedstock source and composition on the process and products.

Background: Carbon-based structural materials are widely studied in the field of renewable energy and environmental sciences. Utilization of abundant, natural, renewable energy precursors together with simple and low energy processes can contribute to reduced emissions of greenhouse gas so is considered as fundamental for manufacturing of sustainable nanostructured materials. Description: Among different resources available for generation of nanostructured materials, plant biomass is superior in terms of economic, environmental and social issues. In addition, transformation of low-value biomass to emerging renewable materials is advantageous compared to dumping and incinerating the biomass. There are a number of techniques and processes for production of nanostructured materials from biomass. Pyrolysis and hydrothermal carbonization (HTC) may be used to convert biomass into nanostructured materials. Objective: This study reviews and compares the production of nanostructured materials from pyrolysis and HTC. Furthermore, the latest developments in pyrolysis and HTC for nanomaterials production are assessed and comparative characteristics are studied for nanomaterials obtained.

The fabrication of magnetic carbon nanostructures is emerging to develop composites with unique properties. Consolidating magnetic nanoparticles with carbon materials can be used in nanoelectronics, catalysis, optical application, biosensors, environmental remediation, energy, hydrogen storage, drug transport, magnetic resonance imaging and cancer diagnosis. In addition, thermochemical methods such as hydrothermal carbonization and pyrolysis are low energy processes that offer an efficient synthesis of the controlled morphology of magnetic carbon nanocomposite. These methods provide chemical and morphological improvements of the structure, such as high surface area, ordered nanosizes, crystal matrix, material stability, electrical conductivity, magnetic saturation and coercivity. This paper reviews the fabrication and properties of magnetic carbon nanocomposites.

In this study, hydrothermal processing was employed to produce crude bio-oil and biochar from waste jujube stones by deploying metal carbonates as catalysts. The effects of metal carbonate catalysts (K2CO3, Na2CO3 and SrCO3) in different concentrations on the product yields and properties were tested for the conversion studies. The use of metal carbonates (K2CO3, Na2CO3 and SrCO3) increased the yield of bio-oil almost twofold, with the highest yield (18.66 wt%) obtained using K2CO3 at a concentration of 10 wt%. (E)- 9-octadecenoic acid (elaidic acid), 2,6-dimethoxyphenol (syringol) and 2-methoxyphenol (guaiacol) were some of the prominent compounds found in the crude bio-oils. The process also resulted in an efficient conversion of jujube stones to biochar with high content of oxygenated functional groups which makes it an effective precursor for various applications. The heating values of the bio-oils and biochars were significantly improved compared to those of the feedstock.

This study introduces a novel concept of rice straw hydrochar incorporation at different loadings (5%, 10%, 15%, and 20%), produced from microwave-induced hydrothermal carbonization (HTC) of rice straw to polylactide (PLA) for production of polylactide/hydrochar (PLA/HC) composites. Higher storage modulus was found for PLA/HC composites than that of neat PLA, confirming the formation of a network structure between PLA and hydrochar. Further, the storage modulus is directly proportional to the amount of hydrochar loading added to the PLA matrix. SEM images suggest that the neat PLA displays a smooth and soft surface. At the same time, PLA/HC blends showed irregular voids and cracks due to the porous structure of hydrochar, allowing PLA to infiltrate through pores of the hydrochar. The tensile modulus of neat PLA was increased from 2.627 GPa for neat PLA to 4.376 GPa, 4.895 GPa, 5.217 GPa, and 6.182 GPa for PLA/HC composites of 5%, 10%, 15%, and 20% hydrochar loadings, respectively. The thermal degradation temperature of the PLA/HC composites was 335–360 °C, which is slightly less than that of neat PLA but still stable up to the range of process and applications of PLA (30–240 °C) without compromising thermal degradation.

Inorganic metal ion additives are being explored for controlling the corrosion and deposition of activated corrosion products on out of core surfaces in Pressurized Heavy Water Reactors (PHWRs). Mg2+ ions can modify the oxides on heat transfer surfaces like Zircaloy and thus influence its corrosion properties. Zircaloy-2 coupons were exposed to simulated Primary Heat Transport (PHT) system environment in the presence and absence of Mg2+ ions and were characterized to understand the surface morphology, defect density and the corrosion protectiveness. Incorporation of Mg into the oxide was confirmed by XPS. GIXRD and Raman spectra showed presence of predominantly monoclinic zirconia with traces of tetragonal phase. GIXRD on Mg-doped films showed that, the monoclinic ZrO2 fraction increased by 2% from 7d to 42d exposure. The films formed in presence of Mg always had higher impedance and lower passive current density than that formed in the absence of Mg for the same duration. This study shows that the Mg doped oxide imparted corrosion protectiveness and the doping is not detrimental to the material.

Novel magnetic bio-nanocomposites were fabricated using polypropylene (PP) as polymer matrix and graphene supported magnetic carbon nanocomposite (MCNC, produced by solvothermal carbonization co-precipitation route integrating low-cost graphene, renewable biomass and iron oxide nanoparticles) serving as filler by incorporating nano-fillers of loading 5%, 10% and 15% with PP using a convenient and time efficient route melt processing. Utilizing waste biomass as integral part of MCNC offers cost effective solution for hybrid nanocomposite synthesis and its application in advance field as electromagnetic interference (EMI) shielding material. The study provides comprehensive analysis for its upgradation in rheological properties that have exclusive impact on its final application. Furthermore, the behaviour for thermal, structural, mechanical, chemical, magnetic, and electrical features using various characterization techniques. Field emission scanning electron micrographs revealed good dispersion of MCNC in PP matrix and formation of network for 15% loading of the filler facilitated 800% higher shielding effectiveness as compared to that of neat PP. It was revealed that functionalization with graphene supported magnetic nanocomposite and polymer matrix have improved the overall conductivity for the composites. Rheological studies indicated the upgradation in viscoelastic properties as solid like behaviour was seen with the increment of filler concentration. X-ray diffractometer demonstrated that MCNC had a substantial impact on the crystallinity of nanocomposite that is validated with modulated differential scanning calorimetry analysis.

Coconut shell derived mesoporous carbon (CS-AC) is explored as prospective supercapacitor component in Li-ion and Na-ion capacitors (LIC and NIC) along with pre-lithiated/sodiated natural plant derived hard carbon (HC) as battery element. Though, there is no obvious variation from the capacitive properties of CS-AC, but an obvious difference is evident for battery component in single electrode configuration. Based on such performance, the mass loading has been adjusted during the fabrication of LIC and NIC. Prior to this, HC is pre-lithiated/sodiated for LIC/NIC assembly. The CS-AC and pre-treated HC based materials registered the maximum energy density of ∼121 and ∼82 Wh kg−1 for LIC and NIC assemblies, respectively. An excellent long-term cycleability of ∼83% retention is noted for LIC after 8000 cycles, whereas NIC showed inferior performance (∼60%) under similar testing conditions. Multilayer surface film is the main reason for such performance which has been clearly revealed from the impedance measurements. First, the CS-AC is prepared by hydrothermal carbonization and subsequent chemical activation with ZnCl2 to yield high specific surface area and pore volume of 1795 m2 g−1 and 2.2 cm3 g−1, respectively, in which 71% originated from mesoporous region.

We report the fabrication of high energy Li-ion capacitor (LIC) using teak wood sawdust derived mesoporous activated carbon (AC-HBP) with electrochemically pre-lithiated graphite (LiC6). Three interesting supercapacitor assemblies are constructed using AC-HBP to realize the high energy density. Amongst, AC-HBP paired with LiC6 delivered a maximum energy density of ∼111 Wh kg−1 compared to Li4Ti5O12 in LIC (∼53 Wh kg−1) and AC-HBP (∼37 Wh kg−1) in symmetric configurations. This excellent energy density is mainly ascribed to the tailored mesoporous nature (∼67%) of the high surface area activated carbon (2108 m2 g−1) obtained via hydrothermal carbonization process in the presence of processing agent, benzene tetracarboxylic acid followed by physico-chemical activation.

A simple and low-cost process of embedding metal nanocrystals as charge storage centers within a dielectric is demonstrated to address leakage issues associated with the scaling of the tunnelling oxide in flash memories. Metal nanocrystals with high work functions (nickel, platinum and palladium) were prepared as embedded species in methyl siloxane spin-on-glass (SOG) films on silicon substrates. Sub-10 nm-sized, well-isolated, uniformly distributed, multi-layered nanocrystals with high particle densities (1011–1012 cm−2) were formed in the films by thermal curing of the spin-coated SOG films containing the metal precursors. Capacitance-Voltage measurements performed on metal-insulator-semiconductor capacitors with the SOG films show that the presence of metal nanocrystals enhanced the memory window of the films to 2.32 V at low operating voltages of ±5 V. These SOG films demonstrated the ability to store both holes and electrons. Capacitance-time measurements show good charge retention of more than 75% after 104 s of discharging. This work demonstrates the applicability of the low-cost in-situ sol-gel preparation in contrast to conventional methods that involve multiple and expensive processing steps.

The tumor suppressor protein p53 is the most frequently inactivated, mutated, or deleted transcriptional factor in tumor cells. Recent studies have shown that the negative regulation of p53 by the murine double minute 2 (MDM2) protein in human cells interrupts the p53 apoptotic pathway and causes tumorigenesis. Therefore, the disruption of the MDM2-p53 complex by small molecules such as nutlin-3a and the administration of the active p53 protein can effectively restore the apoptotic activity of the p53 protein in tumor cells. This study aims to introduce a unique combined p53-based gene and chemotherapy approach using core-shell polymeric microparticles for the localized treatment of cancers. Core-shell microparticles were successfully fabricated in a single step using a modified electrohydrodynamic atomization (EHDA) technique, where the core and shell layers were loaded with nutlin-3a and β-cyclodextrin-g-chitosan/p53 nanoparticles, respectively. The grafting of β-cyclodextrin (β-CD) onto chitosan chains demonstrated remarkable cellular uptake (∼5-fold) compared to pure chitosan at N/P = 6, attributed to a strong interaction and temporary disruption of the lipid bilayer in the cell membrane by the synthesized copolymer. The therapeutic efficiencies of single- and dual-agent loaded microparticle formulations were also evaluated and compared against free-drug treatment in terms of cell viability and intracellular expression of p53, caspase 3, and MDM2 proteins via an MTS assay, an enzyme-linked immunosorbent assay, and an immunostaining assay. The results revealed that the controlled and sustained release of both agents from the microparticles synergistically enhanced the anti-proliferative efficacy of the agents via the continuous overexpression of p53 and caspase 3 proteins over 5 days. However, MDM2 protein expression remained at the basal level over that period. The findings also indicated that nutlin-3a could impose excessive oxidative stress on cancer cells, where the overproduction of reactive oxygen species (ROS) with irreversible destructive effects on subcellular organelles such as the nucleus (DNA) and mitochondria could be considered as a secondary apoptotic pathway induced by nutlin-3a. Inspired by the observations, the proposed drug delivery system can serve as a unique and powerful drug and gene delivery system with a far-reaching application in human cancer therapy.

The leap-forward discovery of nanomaterials and their wide application in varying industries have attracted researchers to perform a further modification to these nanomaterials to improve their application. Iron-based nanomaterials stand out to be one of the highly efficient nanomaterials because of their vast availability and lower production cost compared to other nanomaterials. The production of these carbon-based nanomaterials is focused on utilizing widely available agricultural and nonagricultural biomass waste because of their lower cost and the production of efficient carbon-based nanomaterials. Iron-based nanomaterials found to have favorable properties such as high surface area, improved membrane properties, smaller particle size, and higher tensile strength. These iron-based nanomaterials are utilized for water and wastewater treatment because of their higher efficiency. The demand for clean water in this era of globalization has been increasing because of growth in the industry sector and in the worldwide population as well. Water treatment methods have been facing challenges to providing clean water because of the increase in operational cost, whereas iron-based nanomaterials provide an efficient alternative method for water treatment. This chapter reviews the application of different types of iron-based nanomaterials for water treatment.

The bio-oil was upgraded in sub-supercritical ethanol using metal supported platinum on activated carbon (Pt/AC) and palladium on activated carbon (Pd/AC) as catalysts. The supercritical upgrading process revealed more effective process compared to the subcritical conditions. Esterification during catalytic upgrading of bio-oil remained prominent which facilitates the conversion of acids present in bio-oil into esters in sub-supercritical ethanol. In addition, heavy compounds of crude bio-oil cracked into lighter compounds in the presence of catalysts. Furthermore, the changes in the upgraded bio-oil relative to crude bio-oil was extensively investigated through higher heating value (HHV), elemental analysis, solution pH, chemical composition (GC-MS), chemical functional groups (FTIR), and 13C and 1H nuclear magnetic resonance spectroscopy (NMR). The chemical composition analysis showed a significant decrease in acid fractions in sub-supercritical upgrading process, hence the solution pH varied from 2.5 in bio-oil to 5.3 after supercritical reaction. The HHV of bio-oil increased from 28.55 to 36.4 MJ/kg. This research has shown that crude bio-oil can be efficiently upgraded with carbon-supported metal catalysts in a sub-supercritical upgrading process.

TiO2 nanoparticles with unique crystalline-core/disordered-shell structures were synthesized in a one step process by employing 4-methoxycalix[7]arene nanoreactors. The nanoparticles were anchored on the surface of quartz beads as a monolayer and showed high visible-light driven photocatalytic activity, excellent long term durability and anti-poisoning property. Photocatalytic performance of the TiO2 nanoparticles was tested in a packed bed and complete decolorization of methyl orange was achieved under ultraviolet light or visible light. The decolorization process followed first-order kinetics and showed different behaviors for ultraviolet and visible radiation, while the overall rates of degradation were the same.

Extraction of peroxidase from raw vegetables using supercritical carbon dioxide (scCO 2 ) and its simultaneous application for oxidation of organics in wastewater in the presence of hydrogen peroxide has been demonstrated. Ethanol and phenol were used as the model organic contaminants and potato and cabbage were employed as the sources of peroxidase. The extractions were carried out at 10 MPa for 2 h over a temperature range of 25 °C to 60 °C. Oxidation of ethanol increased by 330% when the treatment was carried out in the scCO 2 medium compared to conventional aqueous medium when cabbage was employed, while use of potato as the enzyme source resulted in an increase of 85%. In the case of phenol, scCO 2 exhibited a huge increase of 400% in presence of cabbage and 140% in presence of potato. Comparison of vegetable extracts with commercial horseradish peroxidase indicated the feasibility, importance and advantage of employing vegetables as a peroxidase source. This work presents the simultaneous extraction of enzymes and its application for oxidation of organics and opens up new opportunities for recovery of resources from unwanted/discarded plant materials and their use for environmental remediation in a single step.

Oxide-free silicon chemistry has been widely studied using wet-chemistry methods, but for emerging applications such as molecular electronics on silicon, nanowire-based sensors, and biochips, these methods may not be suitable as they can give rise to defects due to surface contamination, residual solvents, which in turn can affect the grafted monolayer devices for practical applications. Therefore, there is a need for a cleaner, reproducible, scalable, and environmentally benign monolayer grafting process. In this work, monolayers of alkylthiols were deposited on oxide-free semiconductor surfaces using supercritical carbon dioxide (SCCO2) as a carrier fluid owing to its favorable physical properties. The identity of grafted monolayers was monitored with Fourier transform infrared (FTIR) spectroscopy, high-resolution X-ray photoelectron spectroscopy (HRXPS), XPS, atomic force microscopy (AFM), contact angle measurements, and ellipsometry. Monolayers on oxide-free silicon were able to passivate the surface for more than 50 days (10 times than the conventional methods) without any oxide formation in ambient atmosphere. Application of the SCCO2 process was further extended by depositing alkylthiol monolayers on fragile and brittle 1D silicon nanowires (SiNWs) and 2D germanium substrates. With the recent interest in SiNWs for biological applications, the thiol-passivated oxide-free silicon nanowire surfaces were also studied for their biological response. Alkylthiol-functionalized SiNWs showed a significant decrease in cell proliferation owing to their superhydrophobicity combined with the rough surface morphology. Furthermore, tribological studies showed a sharp decrease in the coefficient of friction, which was found to be dependent on the alkyl chain length and surface bond. These studies can be used for the development of cost-effective and highly stable monolayers for practical applications such as solar cells, biosensors, molecular electronics, micro- and nano- electromechanical systems, antifouling agents, and drug delivery.

This study aims to present a new intelligent polymeric nano-system used for combining chemotherapy with non-viral gene therapy against human cancers. An amphiphilic copolymer synthesized through the conjugation of low molecular weight polyethyleneimine (LMw-PEI) and poly(e-caprolactone) (PCL) via a bio-cleavable disulfide linkage was successfully employed for the simultaneous delivery of drug and gene molecules into target cells. Compared to the conventional PCL copolymerization pathway, this paper represents a straightforward and efficient reaction pathway including the activation of PCL-diol hydroxyl end groups, cystamine attachment and LMw-PEI conjugation which are successfully performed at mild conditions as confirmed by FTIR and 1 H NMR. Thermal, morphological characteristics as well as biocompatibility of the copolymer were investigated. The copolymer showed great tendency to form positively charged nanoparticles (∼163.1 nm, +35.3 mV) with hydrophobic core and hydrophilic shell compartments implicating its potential for encapsulation of anti-cancer drug and plasmid DNA, respectively. The gel retardation assay confirmed that the nanoparticles could successfully inhibit the migration of pDNA at ∼5 nanoparticle/pDNA w/w. The in vitro cytotoxicity tests and LDH assay revealed that the cationic amphiphilic copolymer was essentially non-toxic in different carcinoma cell lines in contrast to branched PEI 25K. Moreover, the presence of redox sensitive disulfide linkages provided smart nanoparticles with on-demand release behavior in response to reducing agents such as cytoplasmic glutathione (GSH). Importantly, confocal microscopy images revealed that in contrast to free Dox, the nanoparticles were capable of faster internalizing into the cells and accumulating in the perinuclear region or even in the nucleus. Finally, the co-delivery of Dox and p53-pDNA using the copolymer displayed greater cytotoxic effect compared with the Dox-loaded nanoparticle counterpart as revealed by cell viability and Caspase 3 expression assay. These results suggest the copolymer as a promising candidate for the development of smart delivery systems. Statement of Significance We employed cystamine dihydrochloride as a disulfide linkage for the conjugation of PCL diol and low molecular weight PEI segments through a straightforward and efficient reaction pathway at mild conditions. The new copolymer was essentially non-toxic in different carcinoma cell lines and showed great tendency to form positively charged nanoparticles. Therefore, it can be utilized as a promising platform for simultaneous drug and gene delivery to aggressive cancers. The results of drug and gene co-delivery experiments confirmed the pivotal role of disulfide linkage on the controlled release of both drug and gene molecules in response to glutathione concentration gradient between extracellular and intracellular microenvironments. In addition, the co-delivery of doxorubicin and p53 plasmid DNA using the new copolymer displayed greater cytotoxic effect compared with single agent (i.e. Dox) loaded counterpart, which indicated the significance of rapid dissociation of therapeutic agents from the carrier for synergistic cytotoxic effects on cancer cells.

Specific surfaces allowing Ultra-High Vacuum (UHV) investigations are required for the successful development of atomic nanostructures. Surface contamination, atomic roughness and defects density must be controlled in order to ensure the reliability of advanced UHV experiments. Surface preparation is a key parameter and is usually conducted in-situ in the UHV chamber. However the surface preparation requires a complex protocol. A microelectronic clean room environment enables the particles density control and enables 200mm wafer scale developments, especially Si(001)-(2x1):H surface reconstruction. However, this passivated surface is reactive and can be easily deteriorated, particularly during transportation. Consequently, a nanopackaging solution is proposed in order to provide a preserving environment for transportation. The nanopackaging process consists in the direct bonding of two passivated silicon surfaces, and is followed by a wafer dicing step into 1cm2 dies. Samples can be stored, shipped and in-situ opened without additional treatment. Furthermore, these samples can provide a reliable surface onto which molecular grafting can be accomplished. The fabrication modules and the associated characterization results will be described as well as atomic nanostructure manipulations and especially the grafting of a self-assembled monolayer using supercritical carbon dioxide as a medium.

Immobilization of enzymes on solid supports is crucial in enzymatic reactions and catalysis as it allows reutilization of soluble enzymes and reduces cost. Covalent immobilization of horseradish peroxidise (HRP) on surface-modified mesoporous activated carbon (SMAC) in combination with supercritical carbon dioxide (scCO2) has been investigated in this study. The supercritical medium achieved higher enzyme loading of 83.5% within 3 h compared to 54% when incubated in aqueous phosphate buffer for 30 h. HRP loading in the scCO2 environment was consistently higher for different HRP: SMAC ratios. The significant increase in the rate and quantity of HRP immobilization is attributed to the favourable transport properties of solutes in scCO2 coupled with greater affinity of HRP for the non-polar supercritical solvent which enhances the diffusivity of enzymes into the porous matrix. Immobilized HRP retained enzymatic activity after being reutilized 11 times which indicated that immobilization did not detract from HRP's activity. The immobilized HRP was successfully employed in removing phenol from water via polymerization of dissolved phenol in the presence of hydrogen peroxide (H2O2). The study shows the advantage of using a mesoporous substrate as the immobilization platform for enzymes in combination with scCO2 as the transport medium. It resulted in significant enhancement in the capacity as well as the uptake rate of HRP and resulting in the enhanced phenol removal.

With the awareness of the need for optimal and sustainable use of natural resources, hydrothermal treatment of biomass and biomass waste for energy and resource recovery has received increasing attention. In this context, hydrochars produced by hydrothermal treatment of biomass, which have been traditionally employed as catalyst supports or adsorbents, are now of considerable interest as precursors for activated carbons. Activated carbon produced from hydrochars has been widely used in applications such as energy storage, environmental remediation and resource recovery. Apart from savings in energy and resource conservation, hydrochars are of interest in activated carbon production because they possess unique attributes such as high density of oxygenated functional groups (OFGs) and low degree of condensation which can be tailored to produce activated carbons with specific and desired characteristics. This review aims to integrate the current knowledge on hydrothermal carbonization of biomass waste in the context of resource and energy recovery. Specifically, we bring together recent advances made in this area through a systematic and critical review of the production of activated carbon from hydrochars. Mechanisms involved in the production of hydrochars with different surface characteristics in response to variations in the operating parameters are critically reviewed. The current knowledge gaps and challenges involved in the hydrothermal carbonization of biomass waste are critically evaluated with suggestions for further research.

Deposition of activated corrosion products on out-of-core surfaces and ensuing radiation field build-up in nuclear reactors calls for remedial measures like decontamination to minimize exposure of service personnel carrying out routine maintenance jobs. Decontamination of stainless steel structural materials in nuclear power plants pose challenges due to the inherent difficulty in dissolving chromium containing oxides like ferrites or chromites. Stainless steel, SS 304LN, is the proposed structural material for the main heat transport system of Indian Advanced Heavy Water Reactors (AHWRs) and it is important to be equipped with an effective decontamination process to mitigate the radiation field build-up in AHWRs. This paper discusses the studies to develop an elevated temperature (ET) decontamination process for SS304LN surface. Oxide covered SS304LN specimens were prepared under simulated AHWR coolant chemistry conditions. The oxide film formed on the specimen surface was Ni and Cr substituted single phase ferrite spinel. The oxide film could be completely dissolved from the SS304LN surface in the nitrilotriacetic acid (NTA) based ET process at 180 °C in a single step with an acceptable and low corrosion rate of 7.7 × 10−3 μm/h. The efficiency of the ET process was compared with the known NTA based conventional low temperature dilute chemical decontamination process and a multi-step, multi-cycle process comprising of alternate oxidation and reduction processes. The ET process proved to be more effective and apt for decontamination of SS304LN surface.

Development of advanced magnetic carbon nano-materials has provided new dimensions in numerous research areas due to their multiple applications. In this study, novel magnetic carbon nano-composites were synthesised by integration of magnetic nanoparticle on novel graphene and renewable carbon materials from rice husk. Magnetic carbon nano-composites were fabricated by hydrothermal carbonization-coprecipitation (HTCC) and solvothermal carbonization-coprecipitation (STCC) routes that are easily scalable. The objective of this work is a comparative study of HTCC and STCC processed and their products. The experiments were conducted using different process variables including process temperatures (180,220 and 260 °C), process time (0.5,1 and 2 h) and solvents (water and ethanol). Chemical interaction of well-dispersed magnetic nano-particles of 5–20 nm size with carbonaceous material was confirmed. Magnetically recoverable nano-composite is highly suitable for use in multiple applications including catalysis, super-capacitance, biosensing devices, environmental remediation and enzymes immobilization and can establish various opportunities for industry in future.

A significant improvement of up to 94% in mesopore area of hydrochar-derived activated carbons (ACs) has been achieved using optimal concentrations of biomass (coconut shell) and chemical activating agent (ZnCl2) during hydrothermal pre-treatment. For the first time, we have demonstrated that stoichiometry can influence hydrochar properties and availability of ZnCl2 for activation which has significant impact on the textural properties of mesoporous activated carbons. Tuning of key process parameters and hydrothermal treatment conditions (ZnCl2:biomass ratios and biomass & ZnCl2 concentrations), together with hydrothermal pre-treatment with H2O2, resulted in BET and mesopore areas up to 2440 m2 g−1 and 1121 m2 g−1, respectively. When the mesoporous carbon was employed as an electrode material in supercapacitors, stable energy density at 7.6 W h kg−1 was observed (90% of 8.5 W h kg−1 @ 0.22 kW kg−1) at a high power density of ∼4.5 kW kg−1, which is one the best performance observed thus far in biomass-derived activated carbons.

We demonstrated the functionalization of one dimensional (1-D) zinc oxide nanorods (ZnO NRs) using bi-functional organic molecules to create hybrid structures with surface functionalities and tuneable organic/inorganic interface. Bi-functional molecules with carboxylic acid, thiol and silane end groups and amine termination had been employed to functionalize the NRs by forming carboxylate, thiolate and hydroxylation bonds, respectively, with ZnO. The surface textures of NRs were preserved even after functionalization. The functionalized NRs were decorated with gold nanoparticles (AuNPs) and the hybrid structures exhibited a quenched blue shift ultraviolet emission which depended on the distance between the ZnO surface and the AuNPs. The NR functionalization with bi-functional molecules and decoration of NPs, and surface morphologies were analyzed using x-ray photoelectron spectroscopy, field emission scanning electron microscopy and transmission electron spectroscopy. These hybrid structures can play a vital role in tuning the interface properties and have potential applications in future photovoltaics, chemical sensors, biomarkers, and wavelength based biosensors. Refereed/Peer-reviewed

This work demonstrates the fabrication of molecular hybrid films comprising gold nanoparticles (AuNPs) incorporated in covalently assembled, substituted polythiophene (poly(3-(2-bromoethoxy)ethoxymethylthiophene-2,5-diyl (PBrEEMT))) films by different surface chemistry routes. AuNPs are incorporated in the immobilized polythiophene matrix due to its affinity for amine and sulfur. The amount of AuNPs present depends on the nature of the incorporation, the extent of film coverage and interaction of thiophene and amine groups. PBrEEMT films functionalized with amine rich polyallylamine immobilize greater numbers of AuNPs due to more extensive gold–amine interactions. Covalent binding between AuNP and PBrEEMT films was accomplished by using pre-functionalised AuNPs (4-aminothiophenol functionalized AuNPs). Atomic force microscopy, field emission scanning electron microscopy and X-ray photoelectron spectroscopy were used to study the morphology and chemical constituents of assembled films. These approaches will pave the way for developing facile methods for nanoparticle incorporation and will also facilitate direct interaction of nanoparticles with the conducting polymer matrix and enhance the electrical properties of the films. Refereed/Peer-reviewed

High-surface area mesoporous activated carbons were prepared from biomass by incorporating H2O2 as an oxidizing agent during hydrothermal pre-treatment of the raw material (coconut shell). Use of H2O2 led to enhanced formation of OFGs in the hydrochar precursor and resulted in activated carbons possessing high mesopore and BET surface areas. A strong interdependence is observed between the extent of formation of oxygenated functional groups (OFGs) in the hydrochars obtained from the hydrothermal pre-treatment and mesopore area in corresponding carbons. The mesoporous carbons showed high adsorption capacity for Rhodamine B up to 714 mg/g.

Formation of dense monolayers with proven atmospheric stability using simple fabrication conditions remains a major challenge for potential applications such as (bio)sensors, solar cells, surfaces for growth of biological cells, and molecular, organic, and plastic electronics. Here, we demonstrate a single-step modification of organophosphonic acids (OPA) on 1D and 2D structures using supercritical carbon dioxide (SCCO2) as a processing medium, with high stability and significantly shorter processing times than those obtained by the conventional physisorption-chemisorption method (2.5 h vs 48-60 h).The advantages of this approach in terms of stability and atmospheric resistivity are demonstrated on various 2D materials, such as indium-tin-oxide (ITO) and 2D Si surfaces. The advantage of the reported approach on electronic and sensing devices is demonstrated by Si nanowire field effect transistors (SiNW FETs), which have shown a few orders of magnitude higher electrical and sensing performances, compared with devices obtained by conventional approaches. The compatibility of the reported approach with various materials and its simple implementation with a single reactor makes it easily scalable for various applications.

Complete photocatalytic degradation of methyl orange, methylene blue and rhodamine chloride was accomplished using immobilized silver nanoparticles as catalysts and tethered calix[7]hydroquinone molecules as nano-reactors. The nanoparticles were immobilized on quartz beads that were assembled in a packed bed configuration. The large interfacial area afforded by the packed bed geometry, presentation of the nanoparticles as a single, tethered layer, and the optically transparent packing material facilitated intimate interaction between the catalyst, dye solution and radiation. The degradation was accomplished using either UV or visible radiation and the nanoparticles displayed self-cleaning and anti-poisoning properties thereby demonstrating excellent durability and catalytic efficiency. The single-layer coverage of Ag nanoparticles facilitates use of very small amounts of the photocatalyst for degradation of relatively large amounts of dye. The method addresses multiple issues that constrain scale-up of photocatalytic systems that deploy nanoparticles as catalysts.