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[en] Based on the ability of some specific aquatic plants to concentrate metals in their roots, we propose an innovative biosorption system to clean up mining effluents. The system we propose represents an interesting solution to an important environmental problem, the decontamination of metal-polluted water and prevention of dispersal of metals into the environment. The solution presented is a form of ecological recycling of Zn, an essential primary metal in many industrial applications. Finally, the methodology developed is a sustainable way of managing the biomass from eradication or control of invasive plants.
[en] The formation of a common mycorrhizal network (CMN) between roots of different plant species enables nutrient transfers from one plant to another and their coexistence. However, almost all studies on nutrient transfers between CMN-connected plants have separately, but not simultaneously, been demonstrated under the same experimentation. Both conspecific and heterospecific seedlings of Cinnamomum camphora, Bidens pilosa, and Broussonetia papyrifera native to a karst habitat in southwest China were concurrently grown in a growth microcosm that had seven hollowed compartments (six around one in the center) being covered by 35.0-μm and/or 0.45-μm nylon mesh. The Ci. camphora in the central compartment was supplied with or without Glomus etunicatum and 15N to track N transfers between CMN-connected conspecific and heterospecific seedlings. The results showed as follows: significant greater nitrogen accumulations, biomass productions, 15N content, % Ntransfer, and the Ntransfer amount between receiver plant species ranked as Br. papyrifera≈Bi. pilosa > Ci. camphora under both M+ and M−, and as under M+ than under M− for Ci. camphora but not for both Bi. Pilosa and Br. papyrifera; the CMN transferred more nitrogen (15N content, % Ntransfer, and Ntransfer amount) from the donor Ci. camphora to the heterospecific Br. papyrifera and Bi. pilosa, with a lower percentage of nitrogen derived from transfer (%NDFT). These findings suggest that the CMN may potentially regulate the nitrogen transfer from a donor plant to individual heterospecific receiver plants, where the ratio of nitrogen derived from transfer depends on the biomass strength of the individual plants.
[en] Microalgal biomass produced from the phycoremediation of wastewater represents an important protein source, lipids, and natural antioxidants and bioproducts. Therefore, the microalgal biomass and their derived compounds are used in animal and aquaculture feed as well as human nutrition and health products. Many microalgal species have shown promising potential for many bioproducts. However, significant processes to find the optimum quality and quantity of microalgal biomass are still required especially when it is used as a replacement for aquaculture feed. The limitations lie in the selection of microalgal species and their production. The present review discusses the potential generation of bioproducts from microalgal biomass resulting from the phycoremediation of wet market wastewater. The consortium approach in wastewater treatment and the comparison between biomass production and available common feeds for aquaculture were reviewed.
[en] Cellulose from bamboo shavings (BC) separated and modified by grafting triphenylphosphine, which was used as an adsorbent for the removal of Acid Black 24 from aqueous solution. The quaternary phosphonium-based bamboo cellulose (PBC) was characterized by FTIR and SEM measurements. The FTIR studies showed that the quaternary phosphonium group was successfully grafted onto the BC molecular structure. The effects of PBC dosage, contact time, initial dye concentration, temperature, and pH on the adsorption performance were studied. The nonlinear fitting kinetics and isotherms models were also conducted. The pseudo-second-order, intra-particle diffusion and Langmuir models were more suitable for analyzing the adsorption behavior of PBC for Acid Black 24 dye. The adsorption activation energy was lower than 40 kJ mol−1, and the ΔH0 value was in the range of 20~80 kJ mol−1, indicating that PBC played a dominant role in the physical purification of dye. The results of thermodynamic analysis indicated that the adsorption was a spontaneous endothermic purification process. Adsorbents had a good reusability and high adsorption performance for dye removal. The adsorbents PBC had a good reusability and could effectively remove residual Acid Black 24 dye with good development prospects in the field of biomass adsorbent materials.
[en] Magnetic carbon aerogels were prepared from inexpensive and readily available winter melon to adsorb U(VI). The morphology, structure, magnetism, characteristic functional groups and chemical bonds of magnetic carbon aerogels were characterized by TEM, SEM, XRD, BET, VSM, FT-IR, XPS. Under the condition of 303 K and pH 6, magnetic carbon aerogel reached adsorption equilibrium within 120 min, with the adsorption capacity of 230.3 mg g-1, much higher than that of carbon aerogel (77.9 mg g-1), which is the function of Fe-O. The good magnetism of magnetic carbon aerogels allows it to be easily separated from the solution by applying magnetic field. The adsorption isotherm data accord with Langmuir isothermal model. Adsorption is a spontaneous and endothermic process. (author)
[en] Furanic and phenolic compounds are problematic compounds resulting from the pretreatment of lignocellulosic biomass for biofuel production. Microbial electrolysis cell (MEC) is a promising technology to convert furanic and phenolic compounds to renewable H2. The objective of the research presented here was to elucidate the processes and electron equivalents flow during the conversion of two furanic (furfural, FF; 5-hydroxymethyl furfural, HMF) and three phenolic (syringic acid, SA; vanillic acid, VA; 4-hydroxybenzoic acid, HBA) compounds in the MEC bioanode. Cyclic voltammograms of the bioanode demonstrated that purely electrochemical reactions in the biofilm attached to the electrode were negligible. Instead, microbial reactions related to the biotransformation of the five parent compounds (i.e., fermentation followed by exoelectrogenesis) were the primary processes resulting in the electron equivalents flow in the MEC bioanode. A mass-based framework of substrate utilization and electron flow was developed to quantify the distribution of the electron equivalents among the bioanode processes, including biomass growth for each of the five parent compounds. Using input parameters of anode efficiency and biomass observed yield coefficients, it was estimated that more than 50% of the SA, FF, and HMF electron equivalents were converted to current. In contrast, only 12 and 9% of VA and HBA electron equivalents, respectively, resulted in current production, while 76 and 79% remained as fermentation end products not further utilized in exoelectrogenesis. For all five compounds, it was estimated that 10% of the initially added electron equivalents were used for fermentative biomass synthesis, while 2 to 13% were used for exoelectrogenic biomass synthesis. The proposed mass-based framework provides a foundation for the simulation of bioanode processes to guide the optimization of MECs converting biomass-derived waste streams to renewable H2.
[en] At present, there are few studies on the quantitative analysis of connectivity from the perspective of biocenology. This study aimed to develop a new quantitative assessment method for river connectivity based on the analysis of the effect of river connectivity on the phytoplankton community in the Shaying River, which has multiple gates. The results showed that from the view of the phytoplankton density and biomass, cryptophytes were the dominant phytoplankton group, but the cyanobacteria density was highest in the summer. In the top 10 of degrees of dominance, there were 4 species of cyanobacteria, 3 species of cryptophytes, 2 species of diatoms, and 1 species of chlorophytes. Based on the seasonal compositions and variations of the phytoplankton community, the river barriers had a great effect on the community. The community composition of the Shaying River has been transformed from a river-type community dominated by diatoms to a lake-type community dominated by cyanophytes. PCA (principal component analysis) indicated that there were obvious differences in the community structure among the sections partitioned by various river gates. According to the relative positions of the entire phytoplankton community and the relative sequence of the river gates, a potential gradient representing the river connectivity can be found; thus, the river connectivity can be quantitatively described from the perspective of the phytoplankton community, and hereby, the corresponding quantitative methods can be established. Characterizing the connectivity of rivers based on biota will facilitate assessing the effects of multiple barriers and understanding river connectivity, and provide the support for the effective management of rivers.
[en] Hierarchical structure composites of loofah derived biomass carbon (PBC) decorated by aligned polyaniline (PANI) were successfully fabricated by simple carbonization and in situ oxidative polymerization. The morphology and structural of composites was studied. The microwave absorbing performance of aligned PANI/PBC was investigated in the frequency range of 2–18 GHz. The results indicated that aligned PANI/PBC with special structure possessed more distinct dielectric response characteristics and enhanced microwave absorbing performance. The minimum reflection loss (RL) value of aligned PANI/PBC was up to − 44.8 dB at 10.02 GHz and the effective absorption frequency width (RL < − 10 dB) is in the 5.58–18 GHz range with the thickness range of 1–3 mm. The excellent microwave absorbing performance of aligned PANI/PBC was mainly correlate with the multiple relaxation polarization, good impedance matching and the synergistic effect between PANI nanorods and PBC.
[en] This study provides a full description of the responses of the crop energy plant Zea mays to stress induced by Cd and Pb, in view of a possible extensive use in phytoattenuation of metal-polluted soils. In this perspective, (i) the uptake capability in root and shoot, (ii) the changes in growth pattern and cytological traits, and (iii) the photosynthetic efficiency based on photochemistry and the level of key proteins were investigated in hydroponic cultures. Both metals were uptaken by maize, with a translocation factor higher for Cd than Pb, but only Cd-treated plants showed a reduced growth compared to control (i.e., a lower leaf number and a reduced plant height), with a biomass loss up to 40%, at the highest concentration of metal (10−3 M). The observation of cytological traits highlighted ultrastructural damages in the chloroplasts of Cd-treated plants. A decline of Rubisco and D1 was observed in plants under Cd stress, while a relevant increase of the same proteins was found in Pb-treated plants, along with an increase of chlorophyll content. Fluorescent emission measurements indicated that both metals induced an increase of NPQ, but only Cd at the highest concentration determined a significant decline of Fv/Fm. These results indicate a different response of Z. mays to individual metals, with Pb triggering a compensative response and Cd inducing severe morpho-physiological alterations at all investigated levels. Therefore, Z. mays could be successfully exploited in phytoattenuation of Pb-polluted soil, but only at very low concentrations of Cd to avoid severe plant damages and biomass loss.
[en] A decrease in the electrical resistance of cable insulation made of plasticized PVC after being infested with the microscopic fungus Aspergillus niger results from an increase in electrical conductivity of the polymer due to adsorption of fungal metabolites. An equation relating the variation of the indicated dielectric parameter with the fungal biomass growing on the polymer material is proposed. The equation can be of value in predicting microbioloically induced deterioration of cable insulation during use.