To evaluate risk via inhalation exposure of polybrominated diphenyl ethers (PBDEs) in office environment, thirty-six pairs air samples including PM2.5 (particles with aerodynamic diameter less than 2.5 μm), PM10 (particles with aerodynamic diameter less than 10 μm), total suspended particles (TSP) with matching gas phase were collected in office environment in Shanghai, China. The average concentrations of PM2.5, PM10 and TSP were 20.4, 27.2 and 50.3 μg/m3, respectively. Σ15PBDEs mean concentrations in PM2.5, PM10, TSP and gas phase were 51.8, 110.7, 148 and 59.6 pg/m3, respectively. Much more PBDEs distributed in fine fractions than coarse ones. PBDEs congener profiles found in PM2.5, PM10 and TSP (dominated by BDE-209) were different from that in gas phase (dominated by the tri- to penta-BDEs). Approximately 3.20 pg/kg/d PM2.5 bound PBDEs can be inhaled into the lung; 3.62 pg/kg/d PM10-PM2.5(particles with aerodynamic diameter of 2.5-10 μm) bound PBDEs tended to be deposited in the upper part of respiratory system, and the intake of PBDEs via gas-phase was 2.74 pg/kg/d. The exposure of PBDEs was far below the minimal risk levels (MRLs), indicating lower risk from PBDEs via inhalation in the studied office in Shanghai.

A novel, small-scale vertical axis wind turbine tree was designed using turbines combining both Darrieus and Savonius blades. We tested for economic viability using wind data collected at a site in Surat Thani, Thailand. The Weibull distribution and Monte Carlo modeling with financial indices (Levelized Cost of Electricity (LCOE), Net Present Value (NPV), Internal Rate of Return (IRR), and Simple Payback Period (SPP)) were used to analyze data. We found that monthly mean wind speeds varied from 2.35 m/s in October to 2.84 m/s in February, corresponding to a wind power of 28.43 W/m2 and 42.68 W/m2. The average annual power output was 1446.1 kWh for May 2019 to April 2021. Results show that for turbine cut-in to cut-out speeds (2 m/s to 15 m/s), the prototype has potential economic feasibility (NPV > 0 for 64.93%), although the small capacity of the wind tree, in combination with the low average wind speed at the Surat Thani test site, showed a lack of economic viability at this specific location (NPV = USD − 20,946.29). A higher-wind-speed location (Chiang Mai) showed viability, especially at a 10 m height (NPV > 0 for 84.83%). We discuss potential conditions that would make broader use of the prototype feasible.

The objective of this study was to investigate the adsorption performance and mechanisms of tetracycline (TC) on hydrochar and hydrochar-derived activated carbon. We also assessed the influence of the solution pH and ionic strength on the adsorption of these compounds and studied their removal by synthetic adsorbents. The maximum adsorption capacities of TC estimated by the Langmuir model in pH 5.5 solution at 25 °C were found to follow the order: ACZ1175 (257.28 mg/g) > MGH (207.11 mg/g) > WAC (197.52 mg/g) > MOPH (168.50 mg/g) > OPH (85.79 mg/g) > GH (75.47 mg/g). The pH value and ionic strength affected TC’s adsorption on the adsorbents. These results indicate that the electrostatic interaction plays a critical role in these adsorption processes. Moreover, adsorption kinetic curves and adsorption isotherms demonstrated that electrostatic interactions were not the only adsorption driving force. Except for electrostatic interactions, the main adsorption mechanisms involved hydrogen bonding and π-π interaction. In addition, the cost of oxidized hydrochar (USD 4.71/kg) is slightly higher than that of hydrochar-derived activated carbon (USD 3.47/kg). This production cost would be lower when it can be produced on a large scale. The outcomes of this study show that the modified-hydrochar and hydrochar-derived activated carbon had the potential for TC removal in wastewater.