Biological impact of lead from halide perovskites reveals the risk of introducing a safe threshold.

Regulations currently in force enable to claim that the lead content in perovskite solar cells is low enough to be safe, or no more dangerous, than other electronics also containing lead. However, the actual environmental impact of lead from perovskite is unknown. Here we show that the lead from perovskite leaking into the ground can enter plants, and consequently the food cycle, ten times more effectively than other lead contaminants already present as the result of the human activities. We further demonstrate that replacing lead with tin represents an environmentally-safer option. Our data suggest that we need to treat the lead from perovskite with exceptional care. In particular, we point out that the safety level for lead content in perovskite-based needs to be lower than other lead-containing electronics. We encourage replacing lead completely with more inert metals to deliver safe perovskite technologies.

Amino-functionalized biomass-derived porous carbons with enhanced aqueous adsorption affinity and sensitivity of sulfonamide antibiotics.

In view of the increasing concerns in antibiotics contamination, advanced technologies for antibiotics removal have been receiving widespread research attention in the fields of environmental sciences. This work has developed a series of amino-functionalized porous carbon materials (NH2-BPCs), via a facile chemical modification method, which have been found efficient for the removal of sulfonamide antibiotics from simulated wastewater. Studies on adsorption kinetics and isotherms of antibiotics in simulated aqueous phases indicated that the adsorption capacity of sulfadiazine (SDZ) by NH2-BPCs showed a large value under acidic conditions (pH < 5). Moreover, the adsorption rate constant of NH2-BPCs was greatly enhanced upon amino modification, which demonstrated faster and more effective adsorption efficiency for antibiotics removal. These results suggested that surface amino modification of porous carbons might be a viable pathway to increase the adsorption affinity and efficiency of antibiotics with great potentials for water remediation.

Assessment of tea garden soils at An'xi County in southeast China reveals a mild threat from contamination of potentially harmful elements.

An extensive study of the spatial distribution characteristics of potentially harmful elements (PHEs) in tea (Camellia sinensis (L.) O. Kuntze) garden soils and ecological risk assessment at An'xi County, the birthplace of oolong tea in China, was implemented. A total of 78 soil samples were examined to determine the concentration of five PHEs (As, Cd, Cr, Hg and Pb), soil organic matter and pH by using geostatistical approaches combined with geographical information system analysis. All PHEs presented in the study area were slightly higher than their background values for provincial and national standards except Cr. Moreover, ecological risk assessment of PHEs in the tea garden soils at An'xi County was performed by means of the Håkanson method. The average ecological potential risk index (Er) of the five PHEs followed a descending order of Cd > Hg > Pb > As > Cr, and suggested a moderate ecological risk in the study area.

Photodegradation of Rhodamine B over Biomass-Derived Activated Carbon Supported CdS Nanomaterials under Visible Irradiation.

A family of new composite materials was successfully prepared through the deposition of as-synthesized CdS nanomaterials on lotus-seedpod-derived activated carbon (SAC). The SAC supports derived at different activation temperatures exhibited considerably large surface areas and various microstructures that were of great importance in enhancing photocatalytic performance of CdS@SAC composite materials toward the photodegradation of rhodamine B (RhB) under visible irradiation. The best-performing CdS@SAC-800 showed excellent photocatalytic activity with a rate constant of ca. 2.40 × 10-2 min-1, which was approximately 13 times higher than that of the CdS nanomaterials. Moreover, the estimated band gap energy of CdS@SAC-800 was significantly lowered down to 1.99 eV compared to that of the CdS precursor (2.22 eV), which suggested considerable strength of interface contact between the CdS and SAC support, as well as efficient light harvesting capacity of the composite material. Further photocatalytic study indicated that the SAC supports enhanced the separation of photogenerated electrons and holes in this system. Improved photocatalytic activity of the composite materials was largely due to the increased generation of catalytically active species such as h+, OH•, [Formula: see text] etc. This work provided a facile and low-cost pathway to fabricate photocatalysts for viable degradation of organic dye molecules.