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This study reports the fabrication of Fe2O3, Bi2O3, and BiFeO3, characterization and evaluation of the photocatalytic performances for methylene blue dye degradation. The materials were synthesized by precipitation method and characterized by scanning electron microscopy, X-ray diffraction, energy dispersive X-rays analyses, and Fourier transform infrared analyses. The photocatalytic activities of Fe2O3, Bi2O3, and BiFeO3 were compared by performing degradation experiments with 50 mL of 100 mg/L methylene blue solution. The as-prepared BiFeO3 was found as 2.4 times and 1.7 times more effective than Fe2O3 and Bi2O3, with a 79, 47, and 57% catalytic activity, respectively. The degradation of methylene blue over the BiFeO3 catalyst was optimized in terms of pH, catalyst dosage, temperature, and methylene blue concentration. The Eley–Rideal mechanism was proposed to describe the reaction kinetics in terms of the first order and second order kinetics model. Activation energy E (kJ/mol), enthalpy ΔH (kJ/mol), entropy ΔS (J/mol) and free energy ΔG (kJ/mol) were calculated as 20.8, 18.2, 197.5 and −45.3 respectively. The negative value of free energy shows that photodegradation is favored in present conditions.

The current investigation was designed to remove halosulfuron methyl from aqueous media by means of neem seed powder (NSP) in batch modes. Characterizations of NSP were carried out by using EDX, SEM, FTIR, point of zero charge and surface analysis. Optimum operation conditions were scrutinized by studying the influence of different factors like solution pH, dose of NSP, contact time, initial halosulfuron methyl concentration and temperature. Result indicates the dependency of the removal of halosulfuron methyl on solution pH and maximal removal (54%) was achieved in acidic medium (i.e. pH 3.0). To identify the chemical surface of NSP, point of zero charge of NSP was determined and was found to be 6.5 which imply that the surface of NSP is positively charged below pH 6.6 and favored the anionic sorption. Kinetics of halosulfuron methyl were demonstrated well by pseudo second order due to highest R2 (0.99) owing to the nearness between experimental and calculated sorption capacities. Isotherm results imply that Langmuir was found to the principal model to explain the removal of halosulfuron methyl and maximum monolayer sorption capacity was determined to be 200 mg g−1. Thermodynamic parameters like ΔH°, ΔG° and ΔS° were calculated from van’t Hoff plot and were found negative which suggest that removal of halosulfuron methyl is exothermic and spontaneous at low temperature. These outcomes insinuate that neem seed power may be a valuable, inexpensive and ecofriendly biosorbent for the removal of pesticides.

The gamma ray induced degradation of moxifloxacin in aqueous media has been evaluated. The drug solutions (50 & 100 mg/L) were irradiated to absorbed doses of 0.3, 0.6, 0.9, 1.2, 1.5, 2, 3 and 4 kGy using Cs-137 gamma radiation source. The parameters such as drug initial concentration, oxidant (H2O2) concentration and gamma ray absorbed doses were optimized. The efficiency of Advanced oxidation processes (AOP) was evaluated on the basis of degradation, reduction in chemical oxygen demand (COD) and toxicity reduction of the drug. The maximum degradation of 94.01 and 88.30% was achieved when drug solutions were exposed to gamma irradiation absorbed dose of 4 kGy which enhanced to 100 and 99.06% in the presence of H2O2 (0.5 mL/L) for 50 and 100 mg/L respectively. A significant reduction in COD 72 and 75% for 50 mg/L while 65 and 69% in case of 100 mg/L was noted using gamma and gamma/H2O2 respectively at absorbed dose of 4 kGy. The parameters such as dose constant (k), removal efficiency (G-value), gamma ray absorbed doses required for 50, 90 and 99% degradation (D 0.50, D 0.90 and D 0.99) have been calculated. The radiolytic degradation was monitored by UV–Vis spectrophotometer and HPLC, FT-IR studies were performed to investigate the change in functional groups before and after treatment, while GC-MS analysis was carried out to monitor intermediates/degraded end-products. The FT-IR spectra has shown complete destruction of aromatic rings after radiation treatment but a minor peak appeared at 1216 cm−1 corresponding to CO stretching. The GC-MS study for the drug samples treated with gamma/H2O2 has shown no any significant peak which confirms the complete degradation. The cytotoxicity of treated samples was carried out by hemolytic assay and mutagenicity using Ames test before and after each treatment. The hemolytic test showed 73.92% hemolysis, while gamma/H2O2 treatment reduced the mutagenicity to 74.08 and 65.66% against TA98 and TA100 bacterial strains respectively. The response surface methodology (RSM) was employed to optimize the data. The obtained data elaborate that gamma/H2O2process is promising approach for the remediation of pharmaceutical waste effluent.

Fe3O4 known as magnetite is one of the oxides of iron which plays a major role in various fields of sciences. Fe3O4 was synthesized by precipitation method using NH3.H2O, FeCl2.4H2O and FeCl3.6H2O as precursor materials. For synthesis of 5% Ag-Fe3O4, the green synthetic method was used for immobilization of Ag nanoparticles on Fe3O4 using leaves extract of Calotropis gigantea plant. The synthesized Fe3O4 and 5% Ag-Fe3O4 were employed as catalyst in degradation of methylene blue. The photo catalytic activity of Fe3O4 was remarkably enhanced by doping of Fe3O4 with Ag nanoparticles. Advanced instrumental techniques including XRD, EDX, TGA and SEM were used for characterization of synthesized particles. The immobilization of Ag on Fe3O4 enhanced the photo degradation of methylene blue from 40 to 72% at 40 °C which confirms that 5% Ag-Fe3O4 is an active catalyst for treatment of dye contaminated water. Ag-Fe3O4 exhibited almost same catalytic activity in two successive cycles. Bull. Chem. Soc. Ethiop. 2020, 34(1), 123-134. DOI: https://dx.doi.org/10.4314/bcse.v34i1.11

Visible light induced photo catalytic degradation of dyes is an inviting approach in wastewater treatment techniques. In this study, silver loaded alumina was synthesized by immobilization of Ag nanoparticles on Al2O3 by facile green method with Azadirachta indica leaves extract and characterized by different advanced techniques. The prepared Ag-Al2O3 particles were tested as photo catalyst on degradation of methylene blue under visible irradiation. Ag-Al2O3 showed improved photo catalytic performance on photo degradation of methylene blue. The deposition of Ag enhanced the photo catalytic activity of Al2O3 from 35 to 95% degradation of methylene blue. Effect of various parameters on catalytic activity were investigated. Curve Expert computer program was used for kinetics analyses of the data according to Langmuir–Hinshelwood and Eley–Rideal mechanism. A 100 mg L−1 solution (50 mL) completely degraded in 120 min of reaction duration at 50 °C over 0.1 g of 3% Ag-Al2O3 as catalyst. 0.01, 0.06 and 0.08 min−1 were calculated as average rate constants at 30, 40 and 50 °C respectively. 25.7 kJ mol−1 was calculated as average activation energy.

Synthetic dyes are persistent pollutants with poor biodegradability. The present study is about the degradation of direct Congo red dye in aqueous media using the Co-60 gamma radiation source. The experimental conditions such as gamma-ray absorbed doses, amount of oxidant (H2O2) and pH conditions were evaluated. The λmax of dye solution was noted as 498 nm, and then, decrease in absorbance and reduction in chemical oxygen demand (COD) were examined. The complete colour removal of dye was observed at 5 kGy, while a significant COD removal was observed at 15 kGy gamma-ray absorbed dose in conjunction with oxidant for 50 mg/L concentration. It was found that pH has no influence on degradation efficiency. A possible degradation pathway was proposed. The radiolytic end products were monitored by Fourier transform infrared (FTIR) and gas chromatography coupled with mass spectrometry (GC-MS) to explore the degradation mechanism. It was imperative to study the oxidative degradation pathway to provide directions for potential applicability of advanced oxidation process (AOP) in industrial wastewater treatment.

Functional surfaces have great significance for improving the performance of bio-devices. The selection of appropriate ways to functionalise the surfaces of the polymers used for bio-devices are in great demand. In particular, cyclic olefin copolymer (COC) and cyclic olefin polymers (COP) are emerging substrates for bio-devices and possess superior chemical resistance than other polymeric substrates such as polycarbonate (PC). These polymer substrates often require surface modification to provide the functionality required. Here, we present a means to functionalise the surfaces of these polymers by a corona discharge treatment method. The water contact angle (WCA) of as received PC, COC and COP was found to be around 80°, 96° and 93°, respectively. The WCA of PC, COC and COP is reduced by 40%, 46% and 44%, respectively when treated with corona dose of 95 W min/m2. The WCA of PC, COC and COP was further reduced by increasing the corona dosage. The reduction of WCA is found mainly due to the incorporation of oxygen-related functionalities (such as carboxylic, carbonyl or aldehyde groups) as confirmed by high-resolution X-ray photoelectron spectroscopy (XPS) and Time-of-flight secondary mass spectrometry (ToF-SIMS). The oxygen to carbon (O/C) ratio is clearly increased after the corona treatment confirming the depletion of carbon on the functional surfaces. The functionality of surfaces obtained by corona treatment could be useful in the development of new bio-devices.

Green manufacturing of catalysts enables sustainable advanced oxidation processes and water treatment processes for removing trace contaminants such as pesticides. An environmentally friendly biosynthesis process produced high-surface-area CuO and NiO nanocatalysts using phytochemicals in the Capparis decidua leaf extract, which served as a reductant and influenced catalyst shape. Capparis decidua is a bushy shrub, widely distributed in dry and arid regions of Africa, Pakistan, India, Egypt, Jordan, Sudan, Saudi Arabia. The synthesized CuO and NiO nanoparticles were characterized by UV-vis spectroscopy (UV-vis), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD) and thermo-gravimetric analysis/differential thermal analysis (TGA/DTA). The produced nanoparticles were spherical and flower-like in shape and have a characteristic face-centered cubic structure of CuO and NiO. Biosynthesized catalysts were photoactive and degraded recalcitrant pesticide Lambda-cyhalothrin (L-CHT). Photocatalytic degradation of L-CHT was affected by the initial L-CHT concentration, solution pH levels between 5 and 9, and photocatalyst concentration. The L-CHT removal percentage attained by CuO photocatalyst (~99%) was higher than for NiO photocatalyst (~89%). The degradation of L-CHT follows a pseudo-first-order kinetic model, and the apparent rate constant (kapp) decreased from 0.033 min−1 for CuO to 0.0084 min−1 for NiO photocatalyst. The novel flower-shaped nanoparticles demonstrated high stability in water and recyclability for removing L-CHT pesticide contamination in water.

Photo catalytic degradation of pollutants is one of the techniques used for treatment of dye contaminated wastewater. TiO2 has attracted much attention as photo catalyst for treatment of contaminated water. In this study, the photo catalytic performance of TiO2 has been enhanced by formation of p–n Co3O4-TiO2 hetero-junction. The p–n Co3O4-TiO2 hetero-junction was prepared by wet incipient impregnation method and characterized by various techniques. The photo catalytic activity of prepared composite was evaluated by photo degradation of methyl orange. The as prepared Co3O4-TiO2 composite was found as effective catalyst than Co3O4 and TiO2. The higher photo catalytic activity was attributed to p–n junction formed between Co3O4 and TiO2. The degradation data was analyzed according to Eley–Rideal mechanism in terms of 1st and 2nd order kinetics.

In this study, Co3O4and Ag-Co3O4were synthesized by a novel and green method using leaves extract ofHelianthus annuusfrom cobalt nitrate and silver nitrate. The synthesized particles were characterized using X-ray powder diffraction, thermal gravimetric analyses, scanning electron microscopy, particle size analyses and UV-Visible spectroscopy. The photo catalytic activities of synthesized Co3O4and Ag-Co3O4were appraised by degrading methyl orange dye and after 120 minutes of reaction a degradation of 53 and 87% was achieved using 100 mg/L (50 mL) solution of methyl orange and 0.1 g Co3O4and Ag-Co3O4as catalyst respectively. This green synthesis of Ag-Co3O4proves to be an eco-benign, environmental benign, simple and effective approach for degradation of dyes in aqueous medium.

The present study investigates a comparative study of the sorption of Cr3+ and Cr6+ from water using an agricultural by-product; mango peels in batch system under the effect of initial metal ion concentrations, solution pH, temperature, sorbent dose and contact time. Characterization of the mango peels was done before and after sorption of Cr3+ and Cr6+ using scanning electron microscopy, surface area pore size analyzer and FTIR spectroscopy. The pH study revealed that that maximum removal of Cr3+ and Cr6+ was obtained at pH 5.0 and 7.0 respectively. Among various kinetic models, pseudo-2nd order well explained the data owing to the higher values of R2 and the nearness between the values of experimental and calculated sorption capacities. The isotherms study revealed that Freundlich is the suitable isotherm for explanation of the equilibrium data due to higher R2 values. The monolayer sorption capacity of mango peels was found to be 98.039 mg g-1 for Cr3+ and 66.666 mg g-1 for Cr6+. The spontaneity and exothermic nature of the sorption process of Cr3+ and Cr6+ using mango peels was reflected from thermodynamic study.

This work was supported by the Marie Curie Initial Training Network (RAPID-ITN, Grant 606889) and by EPSRC (Grants EP/K022237/1 and EP/M024938/1). A.U.H. and S.A. are thankful for the financial support from RAPID-ITN and Ulster University’s Vice Chancellor scholarships, respectively. The knowledge of band edges in nanocrystals (NCs) and quantum-confined systems is important for band alignment in technologically significant applications such as water purification, decomposition of organic compounds, water splitting, and solar cells. While the band energy diagram of bulk silicon carbides (SiCs) has been studied extensively for decades, very little is known about its evolution in SiC NCs. Moreover, the interplay between quantum confinement and surface chemistry gives rise to unusual electronic properties and remains barely understood. Here, we report for the first time the complete band energy diagram of SiC NCs synthesized such that they span the regime from strong to intermediate to weak quantum confinement. The absolute positions of the highest occupied (HOMO) and lowest unoccupied (LUMO) molecular orbitals show clear size dependence. While the HOMO level follows the expected behavior for quantum-confined electronic states, the LUMO energy shifts below the bulk conduction band minimum, which cannot be explained by a simple quantum confinement caused by the size effect. We show that this effect is a result of the interplay between quantum confinement and the formation of surface states due to partial and site-selective oxygen passivation. Publisher PDF

The presence of heavy metals in water causes serious problems and their treatment before incorporating into the water body is a challenge for researchers. The present study was conducted to compare the sorption study of Ni (II) using silica gel, amberlite IR-120 and sawdust of mulberry wood in batch system under the influence of pH, initial Ni (II) concentration and contact time. It was observed that sorption process was depending upon pH and maximum sorption was achieved at pH 7.0. Kinetic data were well fitted into pseudo-second order kinetic model due to high R2 values and closeness of experimental sorption capacity and calculated sorption capacity of pseudo-second order. Isotherms study showed that Langmuir is one of the most suitable choices to explain sorption data due to high R2 values. The monolayer sorption capacities of silica gel, amberlite IR-120 and sawdust were found to be 33.33, 25.19, and 33.67 mg g−1, respectively. Desorption study revealed that NaCl is one of the most appropriate desorbent. It may be concluded from this study that sawdust is a suitable sorbent due to low cost, abundant availability and recycling of the materials for further study.

The plants assisted green synthesis of nanoparticles have drawn a momentous importance worldwide. NiO is one the metal oxides researched comprehensively for decades and still has dominance in the field of photo-catalysis. In present study NiO and Ag–NiO were successfully prepared by a simple and environmentally friendly method using nickel nitrate, silver nitrate and leaves extract of Azadirachta indica L. plant as precursor materials. The prepared materials were characterized by XRD, SEM and TGA. Then the photo-catalytic efficiency of NiO and Ag–NiO were evaluated by aqueous phase photo-degradation of rhodamine B as a model pollutant under ultraviolet irradiations. About 40% and 96% of 200 mg/L (50 mL) degraded in 120 min at 40 °C over NiO and Ag–NiO as photo-catalyst respectively. The apparent rate constants were determined as 0.0109, 0.0165, 0.0175 and 0.0190 per min at 30, 40, 50 and 60 °C respectively. 14.6 kJ/mol was calculated as activation energy of reaction.

In the present study, cantaloupe (Cucumis melo) seed shell powder was utilized to sequester butachlor pesticide from aqueous medium in batch system. The biomass was characterized before and after removal study by SEM, EDX, FTIR and surface area analyzer. The removal study of the butachlor was accomplished concerning the effect of dosage of sorbent, time of contact, solution pH, temperature and initial butachlor concentration. These results indicate that the removal study is considerably pH dependant, and optimum removal (80%) was achieved at pH 3. The butachlor removal data were analyzed by pseudo-first order, pseudo-second order, Elovich, liquid film and intraparticle diffusion. Among these models, pseudo-2nd-order well describes the data owing to not only higher R2 value but also due to a close relationship between experimental and calculated sorption capacity of pseudo-second order. The removal data were also analyzed by Dubinin–Radushkevich, Freundlich, Temkin and Langmuir and were found that Freundlich isotherm explains the data better due to high R2 value. Langmuir isotherm was used to calculate the maximum sorption capacity of cantaloupe seed shell powder and was found to be 142.857 mg g−1 for butachlor. The values of thermodynamic parameters like enthalpy (− 0.068 kJ mol−1), free energy (− 0.646, − 1.255, − 2.032, − 2.787, − 3.414, − 3.989 kJ mol−1) and entropy (− 20.908 kJ mol−1) suggest that the removal of butachlor using cantaloupe seed shell powder is exothermic and spontaneous in nature.

This manuscript reports the solubilization of two reactive dyes viz. reactive black-5 (RB-5) and reactive black-8 (RB-8) in the micellar media of cationic surfactant, cetyl trimethylammonium bromide (CTAB) by differential UV/visible spectroscopy. Absorption spectra of said dyes in the presence of CTAB provide strong evidence about dye–surfactant interaction. In premicellar region ion association pair is formed between dye and surfactant while in post micellar region dye molecules get accommodated within the micelles. The values of critical micelle concentration (CMC) of CTAB in the presence of dyes, partition coefficient; Kx , free energy of partition, ∆Gp , binding constant, Kb and free energy of binding, ∆Gb were determined and compared for both dyes. It is, thus, concluded that RB-5 is solubilized to greater extent than RB-8 because of its incorporation in palisade layer of micelle close to micelle-water interface.

Water pollution by the textile industry is a major issue. Therefore, there is a need for methods to remove organic dyes from industrial effluents. Various metal oxides have been used as catalysts for the degradation of dyes. The catalytic efficiency of metal oxides can be enhanced by doping metal oxides with metals. Here we report the synthesis and characterization of nano-sized mixed valence manganese oxide (Mn x O y ) and silver-doped mixed valence manganese oxide (Ag@Mn x O y ). We study their photo-catalytic efficiency for the photo-degradation of the rhodamine B dye under light irradiation. Mn x O y was prepared using KMnO4, MnSO4 and NH3, and Ag@Mn x O y was prepared using AgNO3 and Calotropis gigantea plant extract. The prepared materials were characterized by X-ray diffractometry, scanning electron microscopy and Fourier transform infrared spectroscopy. Results show that doping with Ag enhanced the photo-catalytic performance of Mn x O y from 11 to 28% and 45 to 91% degradation of rhodamine B dye in 15 and 120 min, respectively. This enhancement is explained by the fact that Ag doping prevents the recombination of photoexcited electrons and positive holes, thus enhancing the photo-catalytic activity of Mn x O y .

We herein report the synthesis of zinc oxide and evaluation of its catalytic performance for degradation of Rhodamine B dye in aqueous medium. Sodium hydroxide and zinc acetate dihydrate were used as precursor materials for synthesis of zinc oxide catalyst. X-ray difractometry, Fourier transform infer red spectroscopy, scanning electron microscopy, thermogravimetric and surface area analyses were used as characterization techniques. Catalytic performance of prepared zinc oxide was evaluated for degradation of Rhodamine B dye in aqueous medium. Catalytic degradation of dye was taking place according to Eley-Rideal mechanism which states that oxygen adsorbed at the surface of ZnO reacts with dye in fluid phase. During the reaction, reactive radicals are formed as a result of electron-hole pair formation between conduction and valence band of zinc oxide catalyst which degrade the dye into water and carbon dioxide.

The present study was carried out to know the sorption mechanism of Pb (II) and Ni (II) in aqueous solution using pea peels under the influence of sorbent dose, pH, temperature, initial metal ion concentration and contact time. SEM and FTIR were used for characterization of pea peels. The study showed that solution pH affects sorption process and the optimum pH for Pb (II) was 6.0 while for that of Ni (II) was 7.0. Pseudo-second order kinetic model was found to be the most suitable one to explain the kinetic data not only due to high value of R2 (>0.99) but also due to the closeness of the experimental sorption capacity values to that of calculated sorption capacity values of pseudo second order kinetic model. It can be seen from the results that Freundlich isotherm explains well the equilibrium data (R2>0.99). Sorption capacity of pea peels was 140.84 and 32.36 for Pb (II) and Ni (II) mg g-1 respectively. The positive value of ΔH° and negative values of ΔG° suggest that sorption of Pb (II) and Ni (II) onto pea peels is an endothermic and spontaneous process respectively.

The present study reports the enhanced solubilizing power of mixed micellar media in comparison to single micellar media. The solubilization of anionic direct dye, Direct Brown 2 (DB-2) has been investigated in micellar media of cationic surfactants; cetyltrimethyl ammonium bromide (CTAB), cetylpyridinium chloride (CPC) and in mixed micellar media of each with nonionic surfactant Triton X-100 (TX-100) using UV–visible spectroscopy and conductometry. The UV–visible spectroscopy has been used to evaluate the degree of solubilization in terms of binding constant, Kb, Gibbs energy of binding, ΔGb, partition coefficient, Kx, and Gibbs energy of partition, ΔGp. Furthermore, electrical conductivity data, taken at different temperatures, has been employed to find out critical micelle concentration (CMC) and different thermodynamic parameters like enthalpy, ΔHm, entropy, ΔSm and Gibbs energy of micellization, ΔGm of reported surfactants in presence of dye. Results reveal spontaneous nature solubilization and binding of dye in both micellar and mixed micellar solutions of surfactants. The micellar system of CTAB as well as mixed micellar solutions of CTAB/TX-100 are recommended to be used to achieve higher degree of solubilization.

This study was focused on the sorption of chlorpyrifos from aqueous media utilizing synthesized zinc oxide nanoparticles impregnated Pea peels (ZnONPs-IPPs) in batch mode under the impact of pH of solution, dosage of sorbent, time of contact, temperature and initial pesticide concentration. The prepared composite was characterized by SEM, EDX, Surface area pore size analyzer and FTIR before and after sorption of chlorpyrifos. It was observed that the sorption of chlorpyrifos depends upon pH and maximal sorption (56%) was occurred at pH 2. The data of sorption process were fitted into Freundlich, Langmuir, Temkin and Dubinin–Radushkevich (D–R) isotherm models and the results indicate that Temkin isotherm is a suitable choice to describe the data owing to higher R2 value (0.99). Monolayer sorption capacity of ZnONPs-IPPs for chlorpyrifos of the Langmuir isotherm was found to be 47.846 mg g−1. Kinetics of sorption were described by fitting data into pseudo-1st-order, pseudo-2nd-order, Elovich, intraparticle and liquid film diffusion models and the results showed that pseudo-2nd order interprets the data well owing to the higher R2 (0.99) well as the close agreement between the calculated and experimental sorption capacity. Thermodynamic parameters ( Δ G ∘ is negative and Δ H ∘ is positive) imply that sorption process of chlorpyrifos utilizing ZnONPs-IPPs is spontaneous and endothermic in nature. The prepared composite is an economical and eco-friendly biomass and may be efficiently used for the removal of other pollutants.

This study explores the lab prepared nickel hydroxide catalyzed oxidative degradation of Methylene Blue (MB) in aqueous medium using batch reactor. Nickel hydroxide was prepared by reaction of sodium hypochlorite, sodium hydroxide and nickel sulphate hexahydrate in distilled water. The catalytic oxidative degradation of Methylene Blue was explored in terms of various parameters like effect of time, hydrogen peroxide, temperature, initial concentration of dye, catalyst dosage and effect of speed of agitation on degradation of Methylene Blue. Experimental data was subjected to kinetics analysis using Curve Expert software. Degradation reaction was taking place according to Langmuir-Hinshelwood mechanism. According to this mechanism the reactants adsorb at the surface of catalyst in first step followed by chemical reaction between adsorbed reactants in second step. Catalyst was heterogeneous in nature which was separated by simple filtration easily.

In this manuscript solubilization of reactive dyes i.e. Reactive red 195 and reactive blue 221, by simple and mixed micellar solution, is being reported using UV/visible spectroscopy and electrical conductivity. UV/visible spectroscopy has been used to have quantitative measurement of degree of solubilization in term of partition coefficient (Kx) and Gibbs energy of partition (ΔGp) while electrical conductivity has been employed to detect critical micelle concentration of surfactants and, accordingly, to calculate thermodynamic parameters. It has been concluded that solubilization is exothermic, spontaneous and enthalpy driven process. The partitioning and binding of RB-195 has been found to be more favorable and spontaneous than that of RB-221. The results clearly indicate that the inclusion of TX-100 in micellar media of CTAB has significantly enhanced its solubilizing power.

This work was supported by the Royal Society International Exchange Scheme (IE120884), the Leverhulme International Network (IN-2012-136), EPSRC (EP/K022237/1 and EP/ M024938/1) and EU-FP7 (award n.606889). S. A. and A. U. H. thank the financial support of the University of Ulster Vice- Chancellor Studentship and EU-funded ITN, respectively (award n.606889). IL and KO acknowledge financial support from CSIRO and Australian Research Council. I. L. acknowledges support from the School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology. Highly size-controllable synthesis of free-standing perfectly crys- talline silicon carbide nanocrystals has been achieved for the first time through a plasma-based bottom-up process. This low-cost, scalable, ligand-free atmospheric pressure technique allows fabri- cation of ultra-small (down to 1.5 nm) nanocrystals with very low level of surface contamination, leading to fundamental insights into optical properties of the nanocrystals. This is also confirmed by their exceptional photoluminescence emission yield enhanced by more than 5 times by reducing the nanocrystals sizes in the range of 1–5 nm, which is attributed to quantum confinement in ultra-small nanocrystals. This method is potentially scalable and readily extendable to a wide range of other classes of materials. Moreover, this ligand-free process can produce colloidal nano- crystals by direct deposition into liquid, onto biological materials or onto the substrate of choice to form nanocrystal films. Our simple but efficient approach based on non-equilibrium plasma environment is a response to the need of most efficient bottom-up processes in nanosynthesis and nanotechnology. Postprint