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In this study, levulinic acid (LA) was produced from rice straw biomass in co-solvent biphasic reactor system consisting of hydrochloric acid and dichloromethane organic solvent. The modified protocol achieved a 15% wt LA yield through the synergistic effect of acid and acidic products (auto-catalysis) and the designed system allowed facile recovery of LA to the organic phase. Further purification of the resulting extractant was achieved through traditional column chromatography, which yielded a high purity LA product while recovering ∼85% wt. Upon charcoal treatment of the resultant fraction generated an industrial grade target molecule of ∼99% purity with ∼95% wt recovery. The system allows the solvent to be easily recovered, in excess of 90%, which was shown to be able to be recycled up to 5 runs without significant loss of final product concentrations. Overall, this system points to a method to significantly reduce manufacturing cost during large-scale LA preparation.

It is now recognized that analytical chemistry must also be a target for green principles, in particular chromatographic methods which typically use relatively large volumes of hazardous organic solvents. More generally, high performance liquid chromatography (HPLC) is employed routinely for quality control of complex mixtures in various industries. Acetonitrile and methanol are the most commonly used organic solvents in HPLC, but they generate an impact on the environment and can have a negative effect on the health of analysts. Ethanol offers an exciting alternative as a less toxic, biodegradable solvent for HPLC. In this work we demonstrate that replacement of acetonitrile with ethanol as the organic modifier for HPLC can be achieved without significantly compromising analytical performance. This general approach is demonstrated through the specific example analysis of a complex plant extract. A benchmark method employing acetonitrile for the analysis of Bidens pilosa extract was statistically optimized using the Green Chromatographic Fingerprinting Response (GCFR) which includes factors relating to separation performance and environmental parameters. Methods employing ethanol at 30 and 80°C were developed and compared with the reference method regarding their performance of separation (GCFR) as well as by a new metric, Comprehensive Metric to Compare Liquid Chromatography Methods (CM). The fingerprint with ethanol at 80°C was similar to or better than that with MeCN according to GCFR and CM. This demonstrates that temperature may be used to replace harmful solvents with greener ones in HPLC, including for solvents with significantly different physiochemical properties and without loss in separation performance. This work offers a general approach for the chromatographic analysis of complex samples without compromising green analytical chemistry principles.

AbstractCoral reefs across the world have been seriously degraded and have a bleak future in response to predicted global warming and ocean acidification (OA). However, this is not the first time that biocalcifying organisms, including corals, have faced the threat of extinction. The end‐Triassic mass extinction (200 million years ago) was the most severe biotic crisis experienced by modern marine invertebrates, which selected against biocalcifiers; this was followed by the proliferation of another invertebrate group, sponges. The duration of this sponge‐dominated period far surpasses that of alternative stable‐ecosystem or phase‐shift states reported on modern day coral reefs and, as such, a shift to sponge‐dominated reefs warrants serious consideration as one future trajectory of coral reefs. We hypothesise that some coral reefs of today may become sponge reefs in the future, as sponges and corals respond differently to changing ocean chemistry and environmental conditions. To support this hypothesis, we discuss: (i) the presence of sponge reefs in the geological record; (ii) reported shifts from coral‐ to sponge‐dominated systems; and (iii) direct and indirect responses of the sponge holobiont and its constituent parts (host and symbionts) to changes in temperature andpH. Based on this evidence, we propose that sponges may be one group to benefit from projected climate change and ocean acidification scenarios, and that increased sponge abundance represents a possible future trajectory for some coral reefs, which would have important implications for overall reef functioning.

Abstract The expansion of Sargassum muticum in the Danish estuary Limfjorden between 1984 and 1997 was followed by a decrease in abundance of native perennial macroalgae such as Halidrys siliquosa. Although commonly associated with the expansion of exotic species, it is unknown whether such structural changes affect ecosystem properties such as the production and turnover of organic matter and associated nutrients. We hypothesized that S. muticum possesses ‘ephemeral’ traits relative to the species it has replaced, potentially leading to faster and more variable turnover of organic matter. The biomass dynamics of S. muticum and H. siliquosa was therefore compared in order to assess the potential effects of the expansion of Sargassum. The biomass of Sargassum was highly variable among seasons while that of Halidrys remained almost constant over the year. Sargassum grew faster than Halidrys and other perennial algae and the annual productivity was therefore high (P/B = 12 year−1) and exceeded that of Halidrys (P/B = 5 year−1) and most probably also that of other perennial algae in the system. The major grazer on macroalgae in Limfjorden, the sea urchin Psammechinus miliaris, preferred Sargassum to Halidrys, but estimated losses due to grazing were negligible for both species and most of the production may therefore enter the detritus pool. Detritus from Sargassum decomposed faster and more completely than detritus from Halidrys and other slow-growing perennial macrophytes. High productivity and fast decomposition suggest that the increasing dominance of S. muticum have increased turnover of organic matter and associated nutrients in Limfjorden and we suggest that the ecological effects of the invasion to some extent resemble those imposed by increasing dominance of ephemeral algae following eutrophication.

The present research was mainly focused on the production of biodiesel from Annona squamosa oil using a synthesized Ni-doped CaO nanocatalyst. The optimization of the transesterification reaction parameters was studied through response surface methodology. The highest biodiesel yield of 99.1% was achieved with the optimized conditions of 7.86% catalyst concentration, 442 RPM, 15.19:1 molar ratio of methanol to oil, reaction temperature of 55.8°C and reaction time of 63.3 min. The results obtained from reaction kinetics study showed a good fit with a first-order kinetic model. The activation energy and R2value were determined to be 53.7 kJ/mol and 0.90, respectively. The synthesized Ni-doped CaO nanocatalyst was characterized using Scanning Electron Microscope with Energy Dispersive X-ray Spectroscopy which confirms the presence of nickel, calcium and oxygen. Also, the average size of the nanocatalyst was found to be 48.79 nm. The Fourier Transform–Infrared Spectroscopy results showed the occurrence of functional groups such as C-H and C = O bonds in the synthesized Ni-doped CaO nanocatalyst. The presence of fatty acid methyl esters in the produced biodiesel was analyzed through Gas Chromatography-Mass Spectrometry analysis. The obtained results from the current study provides the possibility and insights for sustainable biodiesel production and a greener environment.

AbstractNiFe2O4/polythiophene nanocomposite was synthesized by in situ chemical oxidative polymerization of thiophene in NiFe2O4 nanoparticles presence, whereas NiFe2O4 nanoparticles were prepared via coprecipitation method. Fourier transform infrared (FTIR), X‐ray diffraction (XRD), UV–Visible, and SEM, EDX techniques were used for characterization of the nanocomposite. The effect of various parameters such as adsorbent dose, contact time, initial dye concentration, and initial pH of solution on the adsorption of Janus green B (JG) and Fuchsin basic (FB) onto the nanocomposite was optimized by batch studies. The equilibrium uptake data ascribed well to the Langmuir model with maximum adsorption capacity of 143 and 498 mg/g at 303 K for JG and FB, respectively. The exceptional high adsorption capacity of NiFe2O4/polythiophene nanocomposite for JG and FB was ascribed to π‐π and electrostatic interactions. Kinetics studies pointed out that JG and FB removal followed pseudo‐second order model. The negative values of ΔH° (JG: –47.28; FB: −38.00 kJ/mol) and ΔG° (JG: −9.347 to −6.442; FB: −14.16 to – 12.85 kJ/mol) pointed out the feasibility, spontaneity, and exothermic nature of removal process. Negative value of ΔS° (JG: –0.125; FB: –0.078 kJ/mol) suggested decrease in randomness at the solid/liquid interface. The results showed that NiFe2O4/polythiophene is an appealing adsorbent for the uptake of JG and FB dyes from aquatic environment.

Polymer-based multicolor emissive materials have growing demand due to their potential applications in various fields such as full-color displays, bioimaging, and light sources because of their processability and high stability. Herein, we report dual-color emissive hybrid materials based on biocompatible poly(l-lactide) and polyethylene glycol-modified two-dimensional layered double hydroxide quantum dots (PEG-LDHQDs). The morphology of polymer films tunes the spatial distribution of QDs within the polymer matrix, modulating the energy transfer between the QDs and affording the dual emission behavior in the aggregated states. The amorphous hybrid films show single emission (blue) from the finely dispersed QDs (mostly isolated) within the polymer matrix. In contrast, dual emission (blue and red) was observed when the polymer was crystallized due to the possible accumulation of QDs at the interface of crystalline and amorphous phases in the lamellar structure. Furthermore, the dual emission could be enhanced by the aggregation of QDs on the pores of the breath figure pattern constructed on the surface of the hybrid film.