Removal of Antimony in Wastewater by Antimony Tolerant Sulfate-Reducing Bacteria Isolated from Municipal Sludge.

Antimony (Sb), a global and priority controlled pollutant, causes severe environmental issues. Bioremediation by microbial communities containing sulfate-reducing bacteria (SRB) is considered to be among the safest, economical, and environmentally friendly methods to remove Sb from wastewater. However, the roles of SRB species in these communities remain uncertain, and pure cultures of bacteria that may be highly efficient have not yet been developed for Sb removal. In this study, an Sb tolerant community was enriched from municipal sludge, and molecular ecological analysis showed that Escherichia (40%) and Desulfovibrio (15%) were the dominant bacteria. Further isolation and identification showed that the enriched SRB strains were closely related to Cupidesulfovibrio oxamicus, based on the molecular analyses of 16S rRNA and dsrB genes. Among them, a strain named SRB49 exhibited the highest activity in removal of Sb(V). SRB49 was able to remove 95% of Sb(V) at a concentration of 100 mg/L within 48 h under optimum conditions: a temperature of 37-40 °C, an initial pH value of 8, 4 mM of sulfate, and an initial redox potential of 145-229 mV. SEM-EDX analysis showed that SRB49 did not adsorb Sb(V) but reduced and precipitated Sb(V) via the formation of Sb2S3. The results demonstrated the potential roles that pure cultures of SRB species may play in Sb removal and the use of Sb-tolerant SRB strains for Sb remediation.

Flexible Smart Noncontact Control Systems with Ultrasensitive Humidity Sensors.

The development of noncontact humidity sensors with high sensitivity, rapid response, and a facile fabrication process is urgently desired for advanced noncontact human-machine interaction (HMI) applications. Here, a flexible and transparent humidity sensor based on MoO3 nanosheets is developed with a low-cost and easily manufactured process. The designed humidity sensor exhibits ultrahigh sensitivity, fast response, great stability, and high selectivity, exceeding the state-of-the-art humidity sensors. Furthermore, a wearable moisture analysis system is assembled for real-time monitoring of ambient humidity and human breathing states. Benefiting from the sensitive and rapid response to fingertip humidity, the sensors are successfully applied to both a smart noncontact multistage switch and a novel flexible transparent noncontact screen for smart mobile devices, demonstrating the potential of the MoO3 nanosheets-based humidity sensors in future HMI systems.

MoS2-OH Bilayer-Mediated Growth of Inch-Sized Monolayer MoS2 on Arbitrary Substrates.

Due to remarkable electronic property, optical transparency, and mechanical flexibility, monolayer molybdenum disulfide (MoS2) has been demonstrated to be promising for electronic and optoelectronic devices. To date, the growth of high-quality and large-scale monolayer MoS2 has been one of the main challenges for practical applications. Here we present a MoS2-OH bilayer-mediated method that can fabricate inch-sized monolayer MoS2 on arbitrary substrates. This approach relies on a layer of hydroxide groups (-OH) that are preferentially attached to the (001) surface of MoS2 to form a MoS2-OH bilayer structure for growth of large-area monolayer MoS2 during the growth process. Specifically, the hydroxide layer impedes vertical growth of MoS2 layers along the [001] zone axis, promoting the monolayer growth of MoS2, constrains growth of the MoS2 monolayer only in the lateral direction into larger area, and effectively reduces sulfur vacancies and defects according to density functional theory calculations. Finally, the hydroxide groups advantageously prevent the MoS2 from interface oxidation in air, rendering high-quality MoS2 monolayers with carrier mobility up to ∼30 cm2 V-1 s-1. Using this approach, inch-sized uniform monolayer MoS2 has been fabricated on the sapphire and mica and high-quality monolayer MoS2 of single-crystalline domains exceeding 200 µm has been grown on various substrates including amorphous SiO2 and quartz and crystalline Si, SiC, Si3N4, and graphene This method provides a new opportunity for the monolayer growth of other two-dimensional transition metal dichalcogenides such as WS2 and MoSe2.

Tellurophene-Based Random Copolymers for High Responsivity and Detectivity Photodetectors.

Organic photodetectors (OPDs) have attracted great attention because of their advantages including tunable response range, easy processability, and flexibility. Various conjugated polymers have been developed for high-performing OPDs. Herein, a series of tellurophene-based random copolymers containing two typical electron-withdrawing units naphthalene diimide (NDI) and perylene diimide (PDI) are designed and synthesized. Through varying the ratio of PDI/NDI moieties of the analogous polymers, the optophysical properties and film morphology, together with photodetector performances, are systematically tuned. It was demonstrated that the photodetectors based on the polymer with the molar ratio of PDI/NDI units of 70/30 possessed strong photoinduced absorption and favorable morphology via transient absorption spectra and atomic force microscopy studies. As a result, a high responsivity about 19.1 A/W at 600 nm and an excellent detectivity more than 1012 Jones ranging from 350 to 600 nm were successfully achieved, which are among the highest values for OPDs and comparable to inorganic counterparts.

Heterostructured ZnS/InP nanowires for rigid/flexible ultraviolet photodetectors with enhanced performance.

Heterostructured ZnS/InP nanowires, composed of single-crystalline ZnS nanowires coated with a layer of InP shell, were synthesized via a one-step chemical vapor deposition process. As-grown heterostructured ZnS/InP nanowires exhibited an ultrahigh Ion/Ioff ratio of 4.91 × 103, a high photoconductive gain of 1.10 × 103, a high detectivity of 1.65 × 1013 Jones and high response speed even in the case of very weak ultraviolet light illumination (1.87 µW cm-2). The values are much higher than those of previously reported bare ZnS nanowires owing to the formation of core/shell heterostructures. Flexible ultraviolet photodetectors were also fabricated with the heterostructured ZnS/InP nanowires, which showed excellent mechanical flexibility, electrical stability and folding endurance besides excellent photoresponse properties. The results elucidated that the heterostructured ZnS/InP nanowires could find good applications in next generation flexible optoelectronic devices.