Drug firm monitors waste water

Four-in-one multifunctional self-driven photoelectrocatalytic system for water purification: Organics degradation, U(VI) reduction, electricity generation and disinfection against bacteria

This study addresses the energy-intensive nature of conventional wastewater treatment processes and proposes a solution through the development of a green, low-energy, and multifunctional wastewater treatment technology. The research focuses on a multifunctional self-driven photoelectrocatalytic (PEC) system, exploring its four-in-one applications in eliminating organic pollutants, reducing U(VI), generating electrical energy, and disinfecting pathogenic microorganisms. A TiO2-decorated carbon felt (CF@TiO2) cathode is synthesized to enhance interfacial charge transfer, with TiO2 coating improving surface binding sites (edge TiO and adsorbed -OH) for UO22+ adsorption and reduction. The self-driven PEC system, illuminated solely with simulated sunlight, exhibits remarkable efficiency in removing nearly 100 % of uranium within 0.5 h and simultaneously degrading 99.9 % of sulfamethoxazole (SMX) within 1.5 h, all while generating a maximum power output density (Pmax) of approximately 1065 μW·cm-2. The system demonstrates significant anti-interference properties across a wide pH range and coexisting ions. Moreover, 49.4 % of the fixed uranium on the cathode is reduced into U(IV) species, limiting its migration. The self-driven PEC system also excels in detoxifying various toxic organic compounds, including tetracycline, chlortetracycline, and oxytetracycline, and exhibits exceptional sterilization ability by disinfecting nearly 100 % of Escherichia coli within 0.5 h. This work presents an energy-saving, sustainable, and easily recyclable wastewater purification system with four-in-one capabilities, relying solely on sunlight for operation.

An effective and rapidly degradable disinfectant from disinfection byproducts

Chloroxylenol is a worldwide commonly used disinfectant. The massive consumption and relatively high chemical stability of chloroxylenol have caused eco-toxicological threats in receiving waters. We noticed that chloroxylenol has a chemical structure similar to numerous halo-phenolic disinfection byproducts. Solar detoxification of some halo-phenolic disinfection byproducts intrigued us to select a rapidly degradable chloroxylenol alternative from them. In investigating antimicrobial activities of disinfection byproducts, we found that 2,6-dichlorobenzoquinone was 9.0-22 times more efficient than chloroxylenol in inactivating the tested bacteria, fungi and viruses. Also, the developmental toxicity of 2,6-dichlorobenzoquinone to marine polychaete embryos decreased rapidly due to its rapid degradation via hydrolysis in receiving seawater, even without sunlight. Our work shows that 2,6-dichlorobenzoquinone is a promising disinfectant that well addresses human biosecurity and environmental sustainability. More importantly, our work may enlighten scientists to exploit the slightly alkaline nature of seawater and develop other industrial products that can degrade rapidly via hydrolysis in seawater.

Efficient solar hydrogen production coupled with organics degradation by a hybrid tandem photocatalytic fuel cell using a silicon-doped TiO2 nanorod array with enhanced electronic properties

A novel, unassisted, hybrid tandem photocatalytic fuel cell (HTPFC) is constructed by adhering a silicon solar cell (SSC) to the back of a highly-active silicon-doped TiO₂ nanorod array (STNR) for efficient solar hydrogen production coupled with organic compound degradation. The STNR with vertically arranged nanorods is prepared by a facile hydrothermal method and has improved charge transport properties and donor density due to the homogenously distributed silicon in the TiO₂ matrix. As a result, the STNR has a notably enhanced photocurrent density that is as high as ˜0.76 mA cm^-2 at 0.2 V vs Ag/AgCl, which is ˜271% of the photocurrent density of undoped sample. By combining the intriguing features of the STNR and SSC, the HTPFC shows a superior performance for tetracycline degradation and hydrogen production, with a removal ratio of 94.3% after 1.5 h of operation and an average hydrogen generation rate of ˜28.8 μmol h^-1 cm^-2. Compared to conventional PFCs, HTPFCs have improved light absorption and charge transfer, owing to the synergistic effect between the STNR and SSC. The results also indicate that the HTPFC is highly flexible, adaptable, and stable when treating wastewaters with various organics, and a wide range of pH values and salinities.

Highly improved photoelectrocatalytic efficiency and stability of WO3 photoanodes by the facile in situ growth of TiO2 branch overlayers

The development of highly efficient and stable visible-light-responsive photoanode materials is essential for practical photoelectrocatalytic (PEC) applications. In this work, a novel method was proposed to enhance the PEC efficiency and stability of WO3 photoanodes by the facile in situ growth of TiO2 branch overlayers on WO3 nanoplates (TWNP) based on the lattice match between monoclinic WO3 and anatase TiO2. The WO3 nanoplates (WNP) with a fluted body and a thickness of 160 nm were first prepared on tungsten foil by a hydrothermal method. Then, numerous 001-oriented anatase TiO2 branches were directly grown in situ on the WNP with an average thickness of 50 nm and a length of 35 ± 5 nm. TWNP exhibited a photocurrent of ∼2.37 mA cm-2, which is 157% of that of WNP, and showed no obvious decay over 100 h continuous testing, compared to only 11.8% that remained for WNP. During the PEC degradation of phenol, the rate constant was 0.322 h-1 for TWNP while it was only 0.131 h-1 for WNP, and the activity of TWNP remained at 97.2% after 10 repeat tests compared to only 67.4% for WNP. According to the transient photovoltage and transient photocurrent measurements, these improvements can be attributed to the TiO2 branches which enhanced the charge separation efficiency and surface reaction kinetics, and hindered the inactivation of TWNP by providing an atomic-level protective cover. Overall, the in situ wet chemical growth of the TiO2 branches is a meaningful way to overcome WO3's drawbacks, i.e., sluggish surface reaction kinetics, rapid charge recombination and gradual loss of photoactivity, to improve the PEC activity and stability of WO3 photoanodes.

Implementing ecopharmacovigilance in practice: challenges and potential opportunities

Ecopharmacovigilance (EPV) is a developing science and it is currently very unclear what it might mean in practice. We have performed a comparison between pharmacovigilance (PV) and EPV and have identified that there are similarities, but also some important differences that must be considered before any practical implementation of EPV. The biggest difference and greatest challenge concerns signal detection in the environment and the difficulty of identifying cause and effect. We reflect on the dramatic vulture decline in Asia, which was caused by the veterinary use of diclofenac, versus the relative difficulty in identifying the specific causes of intersex fish in European rivers. We explore what EPV might mean in practice and have identified that there are some practical measures that can be taken to assess environmental risks across product life cycle, particularly after launch of a new drug, to ensure that our risk assessments and scientific understanding of pharmaceuticals in the environment remain scientifically and ecologically relevant. These include:

Tracking environmental risks after launch of the product, via literature monitoring for emerging data on exposure and effects

Using Environmental Risk Management Plans (ERMPs) as a centralized resource to assess and manage the risks of a drug throughout its life cycle

Further research, testing or monitoring in the environment when a risk is identified

Keeping a global EPV perspective

Increasing transparency and availability of environmental data for medicinal products.

These measures will help to ensure that any significant environmental issues associated with pharmaceuticals in the environment (PIE) are identified in a timely way, and can be managed appropriately.