Net Trapping Research Articles

Preparation of a novel organic-inorganic composite sludge bioflocculant (SBF) from dewatered sludge as raw material: Characteristics, flocculation mechanism and application for domestic sewage

In this work, a green sludge bioflocculant (SBF) was prepared via chemical hydrolysis of dewatered sludge and applied to flocculation of domestic wastewater. The process parameters for the preparation of the SBF were 1.80 % hydrochloric acid concentration, 60 min extraction time, and 4000 r/min centrifugation speed. SBF is polymeric flocculant composed of organic and inorganic compounds. Flocculation efficiency reached 97.31 ± 0.26 % under optimal flocculation conditions. Charge neutralization promotes the surface adsorption, bridging and net trapping and sweeping of Fe (OH)3, Al (OH)3 and active functional groups OH/NH and C = O in SBF, which together achieve efficient flocculation reactions. SBF had high efficiency and stable flocculation performance for phosphorus in urban domestic wastewater, and the concentration of TP in effluent was lower than 0.30 mg/L. Therefore, SBF prepared from dewatered sludge has efficient flocculation properties and is suitable for removing pollutant phosphorus, which has good application prospects in the field of wastewater treatment.

Optimization of microalgal-bacterial consortium flocculation through chitosan-diatomite composite materials: A sustainable approach to biomass harvesting

Chitosan-based flocculants are emerging as a promising technology for microalgae harvesting. However, the implementation of cost-effective and sustainable chitosan-inorganic composites within algal-bacterial symbiosis (ABS) systems for harvesting microalgal-bacterial consortiums (MBC) is still underdeveloped. This study addresses this gap by synthesizing and evaluating chitosan-diatomite composite materials (CTS/DTE), with a focus on their concentration impact on MBC flocculation. Optimal biomass production and flocculation performance were achieved at a CTS/DTE concentration of 60 mg/L during MBC co-culture. Comprehensive characterizations revealed that the largest particle size significantly contributed to superior flocculation efficiency. This efficacy was primarily attributed to the synergistic effects of net trapping and adsorption cross-linking, facilitated by the unique interaction between CTS and DTE. These interactions not only enhanced the bond between the flocculant and microalgal cells but also promoted the structural stabilization of the MBC flocs. Additionally, tryptophan-like proteins in the extracellular polymeric substances (EPS), as identified through three-dimensional fluorescence (EEM) analysis, were found to be the primary contributor to the hydrophobic properties of MBC flocs, significantly enhancing their adhesion and aggregation thermodynamics. Collectively, this research elucidates innovative strategies and provides both theoretical and practical insights for the efficient and cost-effective harvesting of MBC, underscoring the potential of CTS/DTE composites in enhancing the sustainability of ABS systems.

Whole-Body Multiparametric PET in Clinical Oncology: Current Status, Challenges, and Opportunities.

The interpretation of clinical oncologic PET studies has historically used static reconstructions based on SUVs. SUVs and SUV-based images have important limitations, including dependence on uptake times and reduced conspicuity of tracer-avid lesions in organs with high background uptake. The acquisition of dynamic PET images enables additional PET reconstructions via Patlak modeling, which assumes that a tracer is irreversibly trapped by tissues of interest. The resulting multiparametric PET images capture a tracer's net trapping rate (Ki) and apparent volume of distribution (VD), separating the contributions of bound and free tracer fractions to the PET signal captured in the SUV. Potential benefits of multiparametric PET include higher quantitative stability, superior lesion conspicuity, and greater accuracy for differentiating malignant and benign lesions. However, the imaging protocols necessary for multiparametric PET are inherently more complex and time-intensive, despite the recent introduction of automated or semiautomated scanner-based reconstruction packages. In this Review, we examine the current state of multiparametric PET in whole-body oncologic imaging. We summarize the Patlak methodology and relevant tracer kinetics, discuss clinical workflows and protocol considerations, and highlight clinical challenges and opportunities. We aim to help oncologic imagers make informed decisions about whether to implement multiparametric PET in their clinical practices.

What to monitor? Microplastics in a freshwater lake – From seasonal surface water to bottom sediments

Marine microplastics have received considerable attention, and efforts are underway to develop standardised methods for sampling, sample treatment, and analysis, while the observation of freshwater ecosystems remains relatively overlooked. To address this understudied environment, we present a comprehensive case study on microplastics in an urban lake from Baltic region of Northern Europe covering the seasonal dynamics of microplastics in surface water, deposition rate throughout one year in sediment traps and distribution of microplastics in dated sediment archive to determine the most representative environmental compartment for microplastic pollution monitoring. The following well-established microplastic research methods have been used: Manta trawling for surface water, trapping for assessing microplastics sedimentation rate and coring for sediments. Attenuated total reflection and micro-Fourier transform infrared spectroscopy methods were used to investigate the synthetic nature of identified particles. The sediment core chronology was based on 210Pb and Bayesian Plum model revealing sediment layers to represent even the time before the beginning of plastic mass production (approximately 1950). The surface water microplastic concentrations were higher in summer (5.71 particles/m3) and gradually decreased towards winter (0.75 particles/m3); they were almost 25 times higher in more recent (2018) sediments than in the deeper layers referring to years prior to 1890. Surprisingly, microplastic particles were found in sediments before the year 1950. The microplastic deposition rate was 9.47 particles/cm2/year or 4.31 µg/cm2/year. The most abundant polymers were polyethylene, polystyrene and polypropylene, and the prominent particle shapes were fibres in surface water and fragments in sediments. Our results provide a baseline for evaluating future contamination level changes in highly urbanized area. We recommend the combination of surface water filtering with net and sediment trapping methods for monitoring microplastics in lakes since this method requires little time and financial resources for sampling and processing and produces information on temporal microplastic occurrence and deposition.

MERANCANG JARING INSANG PERMUKAAN UNTUK MENANGKAP IKAN DI TELUK AMBON DALAM

The use of gill nets in fishing is a well-established practice among fishermen due to several factors including ease of material acquisition, simple operational techniques, relatively affordable costs, and high selectivity in catching fish of specific sizes. This study aims to describe the design of fishing gill nets in Inner Ambon Bay. The research was conducted at the Ambon Fisheries Training and Extension Center (BP) in April and May of 2024. The design and construction of surface gillnets for mackerel scad consist of mesh size (inches), fish body circumference, net length, hanging ratio, weights, and distance between floats and weights. The design of the surface gill net with a 2-inch mesh size and a 45% hanging ratio has proven to be effective in catching mackerel scad (Decapterus sp) ranging from 17 cm to 26 cm in length. The use of polyamide (PA) material for the net body provides the necessary strength and flexibility, while the float made of polyvinyl chloride (PVC) and lead weights ensures balanced distribution for optimal functioning in the water. A 45% hanging ratio provides an ideal balance between net length and fish trapping ability, avoiding nets that are too curved or stiff, which can reduce fishing effectiveness.

Assessing Bee (Hymenoptera, Apoidea, Anthophila) Diversity and Floral Preference in Two Habitats in the Iberian Peninsula

The plant-pollinator relationship is one of the most investigated biological processes, not only because of its ecological importance (natural and farming ecosystems) but also its economic profitability (farming and biological products). Current losses of bee populations urge the need to assess the state of wild bee biodiversity in environments such as the Sierra de Guadarrama. Two characteristic sites with different plant diversities were compared by collecting bees using net trapping, a thicket, and a grassland. In this way, not only the possible influence of floral wealth on bee abundance was studied, but also the preference of these Hymenoptera towards any type of flower. Phenological patterns and predominant sex were also studied. 331 bee individuals, belonging to 6 families, 19 genera, and 46 species, were recorded in this study. Our results showed that bee diversity depends not only on environmental factors (temperature or plant composition and abundance) but biological as well (plant-pollinators matches or co-occurring species). Moreover, our study sets a starting point for debating the influence of managed bees (Apis mellifera) on wild bee communities. A preference for a small number of plant species (Cistus ladanifer, Echium vulgare, and Lavandula stoechas) was observed. In addition, there was a relationship between the type of corolla and the tongue length. Our study highlights the importance of this area of the Sierra de Guadarrama for wild bee biodiversity. All things considered, it falls on preserving those ecosystems with high floral wealth to favor the wild bee´s presence and its habitat in the foresight of climate change future scenarios.

Coal gasification crude slag based complex flocculants by two-step acid leaching process: synthesis, flocculation and mechanisms.

Coal gasification crude slag (CGCS) is the side-product of the coal gasification process, and its effective utilization has attracted great attention. A novel flocculant of poly-aluminum-ferric-acetate-chloride (PAFAC) was synthesized based on the recovery of CGCS by a two-step acid leaching process, namely HCl-acid leaching and HAc-acid leaching, which was optimized by an acid leaching liquor volume ratio of HCl to HAc of 3 : 2, polymerization pH of 3.5, and reaction temperature and time of 70 °C and 3.0 h, respectively. The performance of PAFAC was further evaluated by kaolin simulated wastewater, domestic sewage, river water, and aquaculture wastewater. The results revealed that PAFAC was feasible for the removal of turbidity, chemical oxygen demand (COD) and total phosphorus (TP). Moreover, PAFAC was characterized by X-ray Diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray fluorescence spectrometry (XRF) and scanning electron microscopy (SEM), which proved that PAFAC was a kind of amorphous polyionic composite. Additionally, the acid leaching kinetics and flocculation mechanisms were further investigated. It was found that the acid leaching process was followed by the unreacted shrinkage core model, and the flocculation process was dominated by charge neutralization, adsorption bridging and precipitation net trapping. The work is expected to develop a new method for the safe disposal of CGCS and provide a novel way for the preparation of Fe-Al composite flocculants, especially, offering a potential strategy for the promotion of the additional value of the coal chemical industry.

Surveillance on dengue vector Aedes albopictus in Ningbo City in 2021

To analyze the density, distribution and insecticide resistance of Aedes albopictus in Ningbo City in 2021, so as to provide insights into formulation of dengue fever control strategies. Four administrative villages were randomly selected from each county (district) in Ningbo City from April to November, 2021, to investigate the indoor population density of Aedes larvae, and the Breteau index (BI) was calculated. The population density of adult mosquitoes was investigated in residential areas, parks/bamboo forests, waste tire stacking sites/waste stations/construction sites in each county (district). On June 2021, larvae of the natural strain A. albopictus were collected from epidemic sites of dengue fever in Ningbo City in 2018, and raised in laboratory. Then, larvae and female mosquitoes without blood feeding were selected for insecticide resistance bioassays, while insecticide-sensitive strains of A. albopictus served as controls. The resistance of A. albopictus larvae to deltamethrin, beta-cypermethrin, propoxur, temephos and dichlorvos using the impregnation method, and the medium lethal concentration (LC50) and resistance ratio (RR) were calculated. The resistance of adult A. albopictus to beta-cypermethrin, permethrin, deltamethrin, propoxur and malathion was determined using the tube bioassay, and the mosquito mortality was calculated. A total of 10 072 small water containers from 9 935 households were investigated in Ningbo City in 2021, and there were 1 276 containers with Aedes larvae detected, with an average BI of 12.89. Totally 1 422 mosquito nets were allocated and 954 female A. albopictus were captured, with an average net trapping index of 1.34 mosquitoes/(net·hour). Both larval and adult A. albopictus mosquitoes were found from April to November, and the density of larval A. albopictus peaked in September (BI = 21.21), while the density of adult A. albopictus peaked in August, with a net trapping index of 2.38 mosquitoes/(net·hour). The LC50 values of delta-methrin, beta-cypermethrin, propoxur, temephos and dichlorvos were 0.017 4, 0.000 9, 0.364 1, 0.038 1 mg/L and 0.001 6 mg/L against larvae of natural strains of A. albopicchus, with RRs of 49.66, 25.53, 9.65, 2.24 and 6.06, and the mortality rates of adult mosquitoes were 66.00% (66/100), 69.39% (68/98), 25.00% (25/100), 98.97% (96/97) and 100.00% (98/98) 24 hours post-treatment with 0.08% beta-cypermethrin, 0.03% deltamethrin, 0.4% permethrin, 0.05% propoxur, and 0.5% malathion for 24 h, respectively. A. albopictus is widely distributed in Ningbo City, with a high population density and presents high-level resistance to common pyrethroid insecticides. The population density and insecticide resistance of A. albopictus requires to be reinforced.

Magnetic coagulation and flocculation of kaolin suspension using Fe3O4 with plant polyphenol self-assembled flocculants

In this work, magnetic flocculant (Fe3O4@PP) was synthesized using plant polyphenol (PP) as a shaping ligand via in situ self-assembly. Characterization results revealed that Fe3O4@PP exhibited uniform particle size and excellent dispersibility with PP coating amount of 16.4 %. Experimental results suggested that Fe3O4@PP showed excellent turbidity removal efficiency in a wide pH range (3.0–10) and initial turbidity range (50–2000 NTU). Under the optimal conditions, Fe3O4@PP achieved 95.2 % of turbidity removal for simulated kaolin suspension and 96.9 % for actual wastewater. Fe3O4@PP exhibited excellent recycling and reusability properties, with high recycling efficiency of 93.3 % even after the fifth cycle. Microscopic observation revealed the formation process of magnetic flocs, involving particle aggregation, chain and cluster formation, and dense network aggregate formation. The structural characteristics and size of magnetic flocs were found to be significantly influenced by the combined effects of magnetic force, electric charge, van der Waals force, and functional groups on the surface of PP. The extended Deryaguin-Landau-Verwey-Overbeek models indicated that magnetic interactions were the primary mechanism for magnetic flocculation, accompanied by charge neutralization, adsorption bridging, sweeping, and net trapping.

Preparation of Heavy Metal Trapping Flocculant Polyacrylamide-Glutathione and Its Application for Cadmium Removal from Water.

In this study, a heavy metal trapping gel with multiple ligand groups was prepared for the first time using response surface methodology. The gel was produced by condensing and grafting glutathione as a grafting monomer onto the main polyacrylamide chain, based on the Mannich reaction mechanism with formaldehyde. FTIR, SEM, TG-DSC, and zeta potentials were used to characterize the gel. The results demonstrated that the gel was morphologically folded and porous, with a net-like structure, which enhanced its net trapping and sweeping abilities, and that glutathione was used to provide sulfhydryl groups to boost the metal trapping ability of polyacrylamide. Coagulation experiments showed that the highest efficiency of the removal of Cd ions from water samples was achieved when the concentration of polyacrylamide-glutathione was 84.48 mgL-1, the concentration of Cd was 10.0 mgL-1, the initial turbidity was 10.40 NTU, and the initial pH was 9.0. Furthermore, the presence of two cations, Cu and Zn, had an inhibitory effect on the removal of Cd ions. In addition, analysis of the zeta potential revealed the flocculation of polyacrylamide-glutathione. The flocculation mechanism of glutathione is mainly chelation, adsorption bridging, and netting sweeping.

STUDIES CONCERNING THE HARMFUL ENTOMOFAUNA IN SOME VEGETABLE CROPS IN SOUTHERN OLTENIA

The harmful entomofauna has always been of scientific interest, so many researchers are studying how to attack, control and prevent it.This paper aims to provide a scientific contribution on the harmful entomofauna of some vegetable crops in southern Oltenia.Research was carried out in Bratovoești stationary where three methods of entomofauna collection were used, namely: Barber soil trap, entomological net trapping method and the spawning method.A total of 48 species totalling 626 specimens belonging to 14 families were identified.

STUDIES CONCERNING THE USEFUL ENTOMOFAUNA IN SOME VEGETABLE CROPS IN SOUTHERN OLTENIA

Vegetable crops are an important technology group that can be grown in our country.The multiple importance of vegetable crops leads to an increased focus on science and technology.This paper aims to make a special contribution of scientific data on useful entomofauna.The research was carried out in the Bratovoesti stationary where three methods of collecting useful insects were used, namely: the spawning method, the Barber soil trap, and the entomological net trapping method.A total of 61 species belonging to 11 orders with 28 families were identified.

Preparation of Cellulose-Based Flocculant and Its Application in the Enrichment of Vitamin K2 in Fermentation Supernatant.

Nutritional food supplements and pharmaceutical products produced with vitamin K2 as raw materials a very promising market in the global scope. The main production method of vitamin K2 is microbial fermentation, but approximately 50% of vitamin K2 synthesized by the main production strain Bacillus subtilis natto exists in extracellular form, which is not easy to separate and extract. In order to solve this problem, in this study, we synthesized a novel cellulose flocculant, MCC-g-LMA, by grafting reaction using microcrystalline cellulose (MCC) and lauryl methacrylate (LMA) as monomers, and ammonium persulfate as an initiator to flocculate VK2 from the fermentation supernatant. The flocculant was characterized by Fourier transform infrared spectroscopy (FTIR), elemental analysis, and scanning electron microscopy (SEM), and the grafting reaction was successful. When the flocculant dosage was 48.0 mg/L and pH was 5.0, the flocculation rate of the MCC-g-LMA on the fermentation supernatant reached 85.3%, and the enrichment rate of VK2 reached 90.0%. Furthermore, we explored the flocculation mechanism of VK2 by the MCC-g-LMA and speculated that the flocculation mechanism mainly included adsorption bridging, hydrophobic association and net trapping and sweep effect. In this study, the extraction method for trace high-value biological products in the fermentation supernatant was improved, which provided a method and theoretical basis for the efficient separation and purification of VK2 and other terpenoids.

Unconventional CO2 Storage: CO2 Mineral Trapping Predicted in Characterized Shales, Sandstones, and Coal Seam Interburden

Summary Carbon dioxide (CO2) capture from industrial sources including coal combustion, gas processing, cement or steel production, blue hydrogen, or direct air capture, and subsequent geological storage is part of the transition to reduce greenhouse gas emissions. Unconventional and conventional reservoirs provide opportunities for beneficial use such as enhanced recovery, supercritical CO2 (ScCO2) fracturing, and storage of gases such as CO2 and ancillary gases, or potentially hydrogen. The purpose of this study is to use Australian unconventional rock packages to understand the controls on CO2 reactivity and mineral trapping (the most secure form of storage) and compare the potential for CO2 storage. Characterization of core from the Surat, Eromanga, and Cooper basins, Australia, is used to populate CO2 and production water-rock reactivity models. Sensitivity to production water composition and temperature was also tested. Coal seam gas (CSG) reservoir interburden ranged from clay-rich mudstones to interlaminated sandstone and mudstone, and calcite cemented sandstones. The coal seam interburden samples contained high plagioclase and chlorite content. They were predicted to alter to carbonates calcite, ankerite, siderite, and dawsonite mineral trapping CO2. After 30 years, net mineral trapping varied from −0.1 to +0.3 kg CO2/m3, and pH was 4.6–4.9. Net mineral trapping after 1,000 years varied from 5.7 to 16.3 kg CO2/m3 and was 17.1 kg CO2/m3 with higher salinity water. The mineral content had the main control with different lithologies decreasing mineral trapping by 41 or 35% compared with a base case. Overlying plagioclase-rich sandstone trapped 17.1 kg CO2/m3 as calcite, ankerite, dawsonite, and siderite after 1,000 years with the pH increasing to 6. For the quartz-rich oil reservoir sandstone, however, only 0.3 kg CO2/m3 was trapped after 1,000 years. Gas shale and marine black oil shales contained high mica, chlorite, and feldspar content that could be converted to carbonate minerals, mineral trapping CO2. A marine black oil shale mineral trapped 8.3 and 13.9 kg CO2/m3 after 30 and 1,000 years, respectively, as siderite and ankerite. Unconventional reservoirs have a strong potential for mineral trapping during CO2 storage.

Study on the Flocculation Performance of a Cationic Starch‐Based Flocculant on Humic Substances in Textile Dyeing Wastewater

AbstractDissolved organic matter is one of the difficult problems in the treatment of textile dyeing wastewater, among which humic substances are the most harmful to the environment and human health. Herein, cationic starch‐based flocculants are prepared by free radical polymerization of corn starch (St) and methacryloyloxyethyl trimethyl ammonium chloride (DMC) in a redox‐initiated system of ammonium persulfate and sodium bisulfite. Corn starch‐graft‐poly(methacryloyloxyethyl trimethyl ammonium chloride) is denoted as St‐g‐PDMC. The St‐g‐PDMC is comprehensively characterized in terms of structural (element analysis, Fourier transform infrared, X‐ray diffraction, proton nuclear magnetic resonance spectroscopy), morphological (scanning electron microscopy), and thermal (differential scanning calorimetry) properties. Humic acid (HA) solution is selected to simulate negatively charged dissolved organic matter. The flocculation performance and mechanism of St‐g‐PDMC, cationic polyacrylamide (CPAM), and polymerized aluminum chloride (PAC) are systematically investigated. The experimental results show that St‐g‐PDMC functions mainly through the electric neutralization and bridging effect as the flocculation mechanism, CPAM using its own structure and the colloid formed by PAC through hydrolysis is more in line with the bonded bridging and net roll sweep trapping. The combined formulation of St‐g‐PDMC and PAC shows advantages over a single flocculant in the treatment of textile dyeing wastewater, and its cost is evaluated.

Invasive water chestnut hinders tidal wetland development

AbstractConsistent shoreline development and urbanization have historically resulted in the loss of wetlands. However, some construction activities have inadvertently resulted in the emergence of new tidal wetlands, with prominent examples of such anthropogenic wetlands found within the Hudson River Estuary. Here, we utilize two of these anthropogenically created tidal wetlands to explore the sedimentary and hydrologic conditions driving wetland development from a restoration perspective. Tivoli North is an emergent freshwater tidal marsh, while Tivoli South is an intertidal mudflat with vegetation restricted to the seasonal growth of invasive water chestnut during summer months. Using a combination of sediment traps, cores, and tidal flux measurements, we present highly resolved sediment budgets from these two protected bays and parameterize trapping processes responsible for their divergent wetland evolution. Utilizing a 16‐year tidal flux dataset, we observe net sediment trapping in Tivoli North for most years, with consistent trapping throughout the year. Conversely, flux measurements at Tivoli South reveal net sediment loss over the study period, with trapping constrained to the summer months. Here, we explore potential mechanisms responsible for these contrasting accumulation regimes, including initial geological differences, sediment loading, and human land use changes, with a focus on the invasion of emergent aquatic vegetation. Results suggest that water chestnut is contributing to these divergent morphologies by inhibiting sediment trapping and facilitating erosion, thereby preventing marsh nucleation in Tivoli South. The longevity of this dataset highlights the capacity of aquatic vegetation to regulate sediment exchange and geomorphology in enclosed bays when provided with an opportunity to colonize. The results of this project provide evidence to inform the management of restoration projects in river systems with tidal wetlands, especially those affected by invasive species of aquatic vegetation.

Removal effect and mechanism of amphiphilic chitosan modified microbubbles on microcystis aeruginosa

Algal blooms in lake and reservoir water lead to water quality problems, including water odors, algal toxins, and disinfection byproducts. A novel dissolved air flotation process that incorporates positively charged bubbles (PosiDAF) can effectively remove algae in lakes and reservoirs. Chitosan, as a modified bubble agent in the PosiDAF process, has attracted extensive attention due to its natural nontoxicity and good flocculation properties. In this paper, three types of amphiphilic chitosan with different lengths of carbon chains were prepared via amphiphilic modification and were used as bubble modifiers to remove microcystis aeruginosa in the PosiDAF process. The effects of algae removal under different dosage of modifiers were compared, and the role of algal organic matter was investigated. Results showed that the water solubility of chitosan was markedly enhanced after amphiphilic modification, while thermal stability were decreased. When using butyl-N-2 hydroxypropyl trimethyl chitosan ammonium chloride (C4-HTCC), the effect of modified air flotation was the best, and the removal ratio of algae was 93.47% when the C4-HTCC dosage was 1.0 mg/L. The presence of AOM enhanced the overall effect of algae removal, and electrostatic attraction was the primary adhesion mechanism of the microbubble-amphiphilic chitosan-algal organic matter-algal cell system. In addition, adsorption bridging and net trapping also have positive effects on algae removal.

Biopolymer-based flocculants: a review of recent technologies.

Biopolymer-based flocculants have become a potential substitute for inorganic coagulants and synthetic organic flocculants due to their wide natural reserves, environmental friendliness, easy natural degradation, and high material safety. In recent years, with more and more attention to clean technologies, a lot of researches on the modification and application of biopolymer-based flocculants have been carried out. The present paper reviews the latest important information about the base materials of biopolymer-based flocculants, including chitosan, starch, cellulose, and lignin etc. This review also highlights the various modification methods of these base materials according to reaction types in detail. Via the recent researches, the flocculation mechanisms of biopolymer-based flocculants, such as adsorption, bridging, charge neutralization, net trapping, and sweeping, as well as, some other special mechanisms are comprehensively summarized. This paper also focuses on the water treatment conditions, the removal efficiency, and advantages of biopolymer-based flocculants in applications. Further, this review sheds light on the future perspectives of biopolymer-based flocculants, which may make progress in the sources of base materials, modification processes, multi-function, and deepening application researches. We believe that this review can guide the further researches and developments of biopolymer-based flocculants in the future, to develop them with a higher efficiency, a lower cost, more safety, and multi-function for more diversified applications. Graphical abstract

Optical trap for an atom around the midpoint between two coupled identical parallel optical nanofibers

We study the trapping of a ground-state cesium atom in a small region around the midpoint between two coupled identical parallel optical nanofibers. We suggest to use a blue-detuned guided light field in the odd $\mathcal{E}_z$-sine array mode to produce an optical potential with a local minimum of exact zero at the midpoint between the nanofibers. We find that the effects of the van der Waals potential on the total trapping potential around the minimum point are not significant when the fiber separation distance and the power of the guided light field are large. For appropriate realistic parameters, a net trapping potential with a significant depth of about 1 mK, a large coherence time of several seconds, and a large recoil-heating-limited trap lifetime of several hours can be obtained. We investigate the dependencies of the trapping potential on the power of the guided light field, the fiber radius, the wavelength of light, and the fiber separation distance.

Rocket launching activities are associated with reduced insect species richness and abundance in two types of tropical plantations around the Wenchang Satellite Launch Center, southern China

Rocket launches are such rare events that their impacts on the environment or biodiversity are almost never studied. Here we report on changes in local insect diversity in the immediate aftermath of a rocket launch conducted on June 25th, 2016 from the Wenchang Satellite Launch Center, southern China. Rocket fuel emissions and disturbance associated with rocket launches may negatively influence local insect biodiversity. We compared insect community structure before and after the rocket launch in two different tropical tree plantations near the launch site. We studied insect species richness (total species numbers) and abundances (total individuals.of all species) using insect net and mercury lamp trapping in a total of six 20 × 20 m2 plots distributed three each in a mixed plantation of coconut (Cocos nucifera) with 10 native tree species, and a pure coconut plantation. Comparing insect species richness and abundances, we found that species richness and abundances were overall greater in the mixed species plantation compared to the coconut monoculture. We also found that species richness and abundance were overall lower after the launch event. However, there was no significant difference in the response of the two plantations, either in richness or abundance, to the launch disturbance. Therefore, the negative effect appeared indiscriminate with respect to plantation type, and the greater plant diversity or insect diversity in the mixed plantation did not protect against this disturbance. Therefore, the general impact of rocket launching disturbance may be similar to catastrophic disturbances (e.g., typhoons) that cause widespread mortality irrespective of species.