Integration of high-solid digestion and gasification to dispose horticultural waste and chicken manure

To realize full energy recovery from grass and chicken manure(CM), the integration of high-solid anaerobic digestion(HSAD) and gasification was investigated experimentally. The anaerobic biodegradability of grass can be enhanced through codigestion with CM. When the volatile solid(VS) ratio of CM to grass was 20:80, C/N ratio calculated to be 21.70, the cumulative biogas yield was the highest, 237 ml·(g VS)^(-1). The enhancement of biogas production was attributed to the buffering effects of ammonia and rich trace elements in CM. In semi-continuous systems, when the organic loading rate was 4.0 g VS·L^(-1)·d^(-1), the HSAD process was stable, with the average biogas yield 168 ml·(g VS)^(-1). More than 80% fractions of the digestates were volatile matters, which meant that the digestates can be used as feedstock for gasification to produce syngas. The VS ratio of grass to CM had significant overall energy generation through HSAD and gasification. Compared with gasification of digestate,cogasification with woodchips increased syngas yield and low heat value(LHV). Increasing of mass ratio of digestates to woodchips led to the decrease of LHV.

Particle velocity measurement of binary mixtures in the riser of a circulating fluidized bed by the combined use of electrostatic sensing and high-speed imaging

The flow dynamics of binary particle mixtures in the fluidized bed needs to be monitored in order to optimize the related industrial processes.In this paper,electrostatic sensing and high-speed imaging are applied to measure the velocities of polyethylene and sand particles in the binary particle mixtures in fluidization.Experimental studies were conducted on a lab-scale cold circulating fluidized bed.Correlation function between electrostatic signals from upstream and downstream electrodes placed along the riser shows two peaks that represent transit times for the two types of particles.To verify the above results,high-speed imaging was adopted to capture the flow images of particle mixtures.Particle Image Velocimetry and Particle Tracking Velocimetry algorithms were utilized to process the resulted images in order to measure the velocities of polyethylene and sand particles.The reasons for two-peak correlation functions are illustrated based on the frequency spectrums of the mono-solid-phase electrostatic signals and the velocity difference between polyethylene and sand particles.Finally,comparisons on the velocities obtained from electrostatic sensing and high-speed imaging demonstrate the electrostatic sensor can roughly estimate the particle velocity of binary particle mixtures in the near wall region of the circulating fluidized bed.

Soy, soil and beyond

Summary Soy and its quest for future food production.Soy,or soybean(Glycine max),is a leguminous plant that has played a significant role in various civilizations throughout human history.Soybeans are native to East Asia and have been cultivated in China for thousands of years.As a food source,soy has a wide range of uses,they include tofu,tempeh,soy milk,soy sauce,miso,soy-based meat alternatives,desserts and snacks.These products serve as alternatives to animal-based proteins and dairy products for vegetarians,vegans,and individuals with dietary restrictions.In addition,soybean oil is one of the most widely consumed cooking oils globally.It is used for frying,baking,sautéing,and salad dressings due to its mild flavour and high smoke point.Soybean oil is also used as an ingredient in margarine,mayonnaise,and other food products.

Design and fabrication of broadband ultralow reflectivity black Si surfaces by laser micro/nanoprocessing

Light collection efficiency is an important factor that affects the performance of many optical and optoelectronic devices.In these devices,the high reflectivity of interfaces can hinder efficient light collection.To minimize unwanted reflection,anti-reflection surfaces can be fabricated by micro/nanopatterning.In this paper,we investigate the fabrication of broadband anti-reflection Si surfaces by laser micro/nanoprocessing.Laser direct writing is applied to create microstructures on Si surfaces that reduce light reflection by light trapping.In addition,laser interference lithography and metal assisted chemical etching are adopted to fabricate the Si nanowire arrays.The anti-reflection performance is greatly improved by the high aspect ratio subwavelength structures,which create gradients of refractive index from the ambient air to the substrate.Furthermore,by decoration of the Si nanowires with metallic nanoparticles,surface plasmon resonance can be used to further control the broadband reflections,reducing the reflection to below 1.0%across from 300 to 1200 nm.An average reflection of 0.8%is achieved.

Nitrogen-doped graphene nanosheets as reactive water purification membranes

Oxidation of organic pollutants by sulfate radicals produced via activation of persulfate has emerged as a promising advanced oxidation technology to address various challenging environmental issues. The development of an effective, environmentally-friendly, metal-free catalyst is the key to this technology. Additionally, a supported catalyst design is more advantageous than conventional suspended powder catalysts from the point of view of mass transfer and practical engineering applications （e.g. post-use separation）. In this study, a metal-free N-doped reduced graphene oxide （N-rGO） catalyst was prepared via a facile hydrothermal method. N-rGO filters were then synthesized by facile vacuum filtration, such that water can flow through nanochannels within the filters. Various advanced characterization techniques were employed to obtain structural and compositional information of the as-synthesized N-rGO filters. An optimized phenol oxidative flux of 0.036 ＋_ 0.002 mmol.h ~ was obtained by metal-flee catalytic activation of persulfate at an influent persulfate concentration of 1.0 mmol-L 1 and filter weight of 15 rag, while a N-free rGO filter demonstrated negligible phenol oxidation capability under similar conditions. Compared to a conventional batch system, the flow-through design demonstrates obviously enhanced oxidation kinetics （0.036 vs. 0.010 retool-h-I）, mainly due to the liquid flow through the filter leading to convection-enhanced transfer of the target molecule to the filter active sites. Overall, the results exemplified the advantages of organic compound removal by catalytic activation of persulfate using a metal-free catalyst in flow- through mode, and demonstrated the potential of N-rGO filters for practical environmental applications.

AIEgen based light-up probes for live cell imaging

Fluorescent light-up probes comprising a tetraphenylethene unit with aggregation-induced emission(AIE)characteristics and a water-soluble peptide have been designed and synthesized which provide cell membrane and nuclear permeability to live cells.This strategy has offered new opportunities for the development of probes with light-up ability and good signal-to-noise ratio.The selectivity or targeting specificity is determined by the peptide sequence,i.e.a nuclear localization signal that leads to nucleus imaging and a cell biomarker targeting peptide that offers specific light-up imaging of HT-29 cells.

Heavy metals in a typical city-river-reservoir system of East China:Multi-phase distribution,microbial response and ecological risk

The rapid construction of artificial reservoirs in metropolises has promoted the emergence of city-river-reservoir systems worldwide.This study investigated the environmental behaviors and risks of heavy metals in the aquatic environment of a typical system composed of main watersheds in Suzhou and Jinze Reservoir in Shanghai.Results shown that Mn,Zn and Cu were the dominant metals detected in multiple phases.Cd,Mn and Zn were mainly presented in exchangeable fraction and exhibited high bioavailability.Great proportion and high mobility of metals were found in suspended particulate matter(SPM),suggesting that SPM can greatly affect metal multi-phase distribution process.Spatially,city system(Ci S)exhibited more serious metal pollution and higher ecological risk than river system(Ri S)and reservoir system(Re S)owing to the diverse emission sources.Ci S and Re S were regarded as critical pollution source and sink,respectively,while Ri S was a vital transportation aisle.Microbial community in sediments exhibited evident spatial variation and obviously modified by exchangeable metals and nutrients.In particular,Bacteroidetes and Firmicutes presented significant positive correlations with most exchangeable metals.Risk assessment implied that As,Sb and Ni in water may pose potential carcinogenic risk to human health.Nevertheless,Re S was in a fairly safe state.Hg was the main risk contributor in SPM,while Cu,Zn,Ni and Sb showed moderate risk in sediments.Overall,Hg,Sb and Ci S were screened out as priority metals and system,respectively.More attention should be paid to these priority issues to promote the sustainable development of the watershed.

Metabolites change of Scenedesmus obliquus exerted by AgNPs

With increasing emission of silver nanoparticles(AgNPs) into the environment, it is important to understand the effects of ambient concentration of AgNPs. The biological effects of AgNPs on Scenedesmus obliquus, a ubiquitous freshwater microalgae, was evaluated. AgNPs exerted a minor inhibitory effect at low doses. Non-targeted metabolomic studies were conducted to understand and analyze the effect of AgNPs on algal cells from a molecular perspective. During the 48 hr of exposure to AgNPs, 30 metabolites were identified, of which nine had significant changes compared to the control group. These include D-galactose, sucrose, and D-fructose.These carbohydrates are involved in the synthesis and repair of cell walls. Glycine, an important constituent amino acid of glutathione, increased with AgNP exposure concentration increasing, likely to counteract an increased intracellular oxidative stress. These results provide a new understanding of the toxicity effects and mechanism of AgNPs. These metabolites could be useful biomarkers for future research, employed in the early detection of environmental risk from AgNPs.

Molecular insights of organochlorine biocide-induced toxicity in zebrafish:Whole-adult-organism toxicogenomics,targeted gene expression and histological analyses

Organochlorine biocides （OCBs）, such as lindane and dichlorodi- phenyltrichloroethane （DDT）, have been used for control of vector- borne diseases in public health and for insect pest control in agri- culture. These chemicals are extremely persistent in the environ- ment and they tend to bioaccumulate via food chains, thus posing risk to human and ecological health （Cooney et al., 2010; Wang et al., 2013）. Due to their persistence in the environment and continuous use in certain countries despite the banning of some of these chemicals, monitoring and studies of OCBs have continued intensely and remain relevant in foreseeable future （ Cohn et al.,

Valorization of poly-β-hydroxybutyrate(PHB)-based bioplastic waste in anaerobic digesters of food waste for bioenergy generation:reactor performance,microbial community analysis,and bioplastic biodegradation

This study aims to investigate the significance and biodegradation pathways of PHB-based bioplastic in anaerobic digesters treating food waste,where the reactor performance of changed methane generation,bioplastic biodegradation efficiency,and bioinformatic analysis of functional microbes were emphasized.The results showed that PHB-based plastic film could be partially biodegraded in the food waste digester,and a bioaugmentation use of Alcaligenes Faecalis(AF)and Bacillus Megaterium(BM)was beneficial to largely accelerate the degradation process through a beneficial shift of both the functional bacterial and archaeal species.Microbial community analysis indicated that the major bacterial species belonged to genera Candidatus_Cloacimonas,Rikenellaceae,and Defluviitoga,while the dominant methanogenic archaeal species belonged to genera Methanomassiliicoccus,Methanosarcina,and Methanosaeta.Bioplastic biodegradation analysis suggested that the optimal fractions of AF and BM for PHB-based plastic degradation were 50% AF and 75% BM,respectively,which deserves further optimization and scale-up validation.The finding of this study would contribute to the combined management of PHB-based bioplastic with food waste for clean energy recovery and a greener environment.