Aqueous rechargeable ammonium ion batteries based on MoS2/MXene with a ball-flower morphology as an anode and NH4V4O10 with a layered structure as a cathode.

Due to the small hydrated ionic radius and light molar mass of ammonium ions, aqueous ammonium ion batteries attract much attention, providing high security, environmental friendliness and low cost. However, the lack of suitable electrode materials with high specific capacity is a big challenge for practical application. Therefore, in view of this problem, we fabricated an anode applying a MoS2 material with a ball-flower morphology anchored to MXene nanoflakes, and it shows excellent rate capability in a novel aqueous ammonium ion battery. The corresponding charge capacities of composite electrodes are 279.2, 204.4, 173.2, 118.7, and 80.5 mA h g-1 at 20, 50, 100, 200, and 500 mA g-1, respectively. Meanwhile, polyvanadate was selected as a cathode material for a full aqueous ammonium ion battery, and interestingly it was discovered that the size of this material decreases with increasing synthesis temperature. The discharge capacities of NH4V4O10 electrodes fabricated at 140 °C, 160 °C, and 180 °C at 50 mA g-1 are 88.6, 125.1 and 155.5 mA h g-1, respectively. Furthermore, we also explore the corresponding electrochemical mechanism using XRD and XPS. A full aqueous ammonium ion battery based on both electrodes shows superior ammonium ion storage properties and provides new ideas for the development of this strategy.

A novel cellulose/chitosan composite nanofiltration membrane prepared with piperazine and trimesoyl chloride by interfacial polymerization.

Bamboo cellulose (BC) is one of the most abundant renewable, hydrophilic, inexpensive, and biodegradable organic materials. The cellulose membrane is one of the best materials for replacing petroleum-based polymer films used for water purification. In this study, N-methylmorpholine-N-oxide (NMMO) was used as a solvent to dissolve cellulose and chitosan, and a regenerated cellulose/chitosan membrane (BC/CSM) was prepared by phase inversion. A new kind of cellulose/chitosan nanofiltration membrane (IP-BC/CS-NFM) was obtained by the interfacial polymerization of piperazine (PIP) and trimesoyl chloride (TMC). The IP-BC/CS-NFM was characterized by Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), thermal gravimetric analysis (TGA), the retention rate, and water flux. FT-IR analysis showed that polypiperazine amide was formed. Additionally, FE-SEM and AFM showed that a uniform roughness and dense functional layer was formed on the surface of the IP-BC/CS-NFM. Furthermore, TGA analysis showed that the thermal stability of IP-BC/CS-NFM is better than that of BC/CSM. The inorganic salt retention of IP-BC/CS-NFM was measured using a membrane performance evaluation instrument, following the order R(Na2SO4) > R(MgSO4) > R(MgCl2) > R(NaCl). At a pressure of 0.5 MPa, the retention rates for NaCl, Na2SO4, MgSO4, MgCl2, Methyl Orange, and Methyl Blue were 40.26%, 71.34%, 62.55%, 53.28%, 93.65%, and 98.86%, and the water flux values were 15.64, 13.56, 14.03, 14.88, 13.28, and 12.35 L m-2 h-1, respectively. The IP-BC/CS-NFM showed better water flux and a higher rejection rate in aqueous dye-salt solutions, and had a good separation performance under different operating pressure conditions.

Removal of benzene, toluene, xylene and styrene by biotrickling filters and identification of their interactions.

Biotrickling filters (BTFs) are becoming very potential means to purify waste gases containing multiple VOC components, but the removal of the waste gases by BTF has been a major challenge due to the extremely complicated interactions among the components. Four biotrickling filters packed with polyurethane foam were employed to identify the interactions among four aromatic compounds (benzene, toluene, xylene and styrene). The elimination capacities obtained at 90% of removal efficiency for individual toluene, styrene and xylene were 297.02, 225.27 and 180.75 g/m3h, respectively. No obvious removal for benzene was observed at the inlet loading rates ranging from 20 to 450 g/m3h. The total elimination capacities for binary gases significantly decreased in all biotrickling filters. However, the removal of benzene was enhanced in the presence of other gases. The removal capacities of ternary and quaternary gases were further largely lowered. High-throughput sequencing results revealed that microbial communities changed greatly with the composition of gases, from which we found that: all samples were dominated either by the genus Achromobacter or the Burkholderia. Different gaseous combination enriched or inhibited some microbial species. Group I includes samples of BTFs treating single and binary gases and was dominated by the genus Achromobacter, with little Burkholderia inside. Group II includes the rest of the samples taken from BTFs domesticated with ternary and quaternary gases, and was dominated by the genus Burkholderia, with little Achromobacter detected. These genera were highly associated with the biodegradation of benzene series in BTFs.

Performance of a combined system of biotrickling filter and photocatalytic reactor in treating waste gases from a paint-manufacturing plant.

A pilot-scale biotrickling filter (BTF) was established in treating the waste gases that are intermittently produced from an automobile paint-manufacturing workshop. Results showed that the BTF required longer time to adapt to the aromatic compounds. The removal efficiencies (REs) for all aliphatic compounds reached more than 95% on day 80. Aromatic compounds were not easily removed by the BTF. The REs obtained by the BTF for toluene, ethylbenzene, m-xylene, o-xylene and p-xylene on day 80 were 72.7%, 77.2%, 71.9%, 74.8% and 60.0%, respectively. A maximum elimination capacity (EC) of 13.8 g-C m(-3) h(-1) of the BTF was achieved at an inlet loading rate of 19.4 g-C m(-3) h(-1) with an RE of 72%. Glucose addition promoted the biomass accumulation despite the fact that temporal decrease of REs for aromatic compounds occurred. When the inlet loading rates exceed 11.1 g-C m(-3) h(-1), the REs of the aromatic compounds decreased by 10% to 15%. This negative effect of shock loads on the performance of the BTF can be attenuated by the pre-treatment of the photocatalytic reactor. Nearly all components were removed by the combined system with REs of 99%.

[Removal of BTEX by a biotrickling filter and analysis of corresponding bacterial communities].

The pre-acclimated microbial consortium and the activated sludge were used as start inoculums of a bench-scale biotrickling filter (BTF). The performance of the biotrickling filter on the removal of BTEX mixture was evaluated, and the changes in the bacterial community structure of the BTF were analyzed by PCR-DGGE technique. The results showed that the BTF could be acclimated within a short time, the biomass that adhered to the surface of packing materials increased rapidly from 5.7 mg x g(-1) at 10th day to 112 mg x g(-1) at 30th day. BTF could simultaneously remove all components of the BTEX mixture efficiently. The maximum removal capacity of the BTF was 216.6 g x (m3 x h)(-1), which was achieved with an inlet loading rate of 269.7 g x (m3 x h)(-1) and an empty bed retention time (EBRT) of 39 s. DGGE analysis indicated that the dominant microorganisms may be derived from the pre-acclimated microbial consortiums rather than the activated sludge. Although the bacterial community changed with run time, the spatial distribution was very uniform.

[Emission characteristics and safety evaluation of volatile organic compounds in manufacturing processes of automotive coatings].

Emission characteristics of volatile organic compounds (VOCs) were investigated in an automotive coating manufacturing enterprise. Air samples were taken from eight different manufacturing areas in three workshops, and the species of VOCs and their concentrations were measured by gas chromatography-mass spectrometry (GC-MS). Safety evaluation was also conducted by comparing the concentration of VOCs with the permissible concentration-short term exposure limit (PC-STEL) regulated by the Ministry of Health. The results showed that fifteen VOCs were detected in the indoor air of the automotive coatings workshop, including benzene, toluene, ethylbenzene, xylene, ethyl acetate, butyl acetate, methyl isobutyl ketone, propylene glycol monomethyl ether acetate, trimethylbenzene and ethylene glycol monobutyl ether, Their concentrations widely ranged from 0.51 to 593.14 mg x m(-3). The concentrations of TVOCs were significantly different among different manufacturing processes. Even in the same manufacturing process, the concentrations of each component measured at different times were also greatly different. The predominant VOCs of indoor air in the workshop were identified to be ethylbenzene and butyl acetate. The concentrations of most VOCs exceeded the occupational exposure limits, so the corresponding control measures should be taken to protect the health of the workers.