We show in theory, simulations, and experiments that, by applying random metallic nanomeshes, a broad-band multilayered structure with a 12 nm thick a-Si film as the active layer can absorb 89% of the total solar energy in the visible range from 400 nm to 700 nm. Such broadness and high absorption can be attributed to the random scattering introduced by the aperiodic metallic nanomeshes and the plasmonic-metamaterial design. The broadband and smooth electromagnetic response, combined with a very high absorption, is desired for solar energy harvesting devices, making this structure a good candidate for high efficiency photovoltaics with ultra-thin active layers.

An environmentally friendly pore size-controlled, superhydrophobic polylactic acid (PLA) membrane was successfully prepared by a simpler freeze solidification phase separation method (FSPS) and solution impregnation, which has application prospects in the field of oil–water separation. The pore size and structure of the membrane were adjusted by different solvent ratios and solution impregnation ratios. The PLA-FSPS membrane after solution impregnation (S-PLA-FSPS) had the characteristics of uniform pore size, superhydrophobicity and super lipophilicity, its surface roughness Ra was 338 nm, and the contact angle to water was 151°. The S-PLA-FSPS membrane was used for the oil–water separation. The membrane oil flux reached 16,084 L·m⁻²·h⁻¹, and the water separation efficiency was 99.7%, which was much higher than that of other oil–water separation materials. In addition, the S-PLA-FSPS membrane could also be applied for the adsorption and removal of oil slicks and underwater heavy oil. The S-PLA-FSPS membrane has great application potential in the field of oil–water separation.

In this study, the pretreatment feasibility of fallen leaves for the removal of heavy metals in aquatic environments was evaluated. The arborvitae leaves were selected as representative and characterized by Brunauer–Emmett–Teller (BET) and FT-IR. BET analysis showed that the surface area of arborvitae leaves was 29.52 m²/g with the pore diameter ranging from 2 to 50 nm. Absorption bands in FT-IR were assigned to C–H, O–H, C–O, and C=O groups, which were the main sites for heavy metals adsorption. With the arborvitae leaves as a natural adsorbent, the removal of Pb(II), Cu(II), and Co(II) ions in the single and ternary component systems was studied by means of batch adsorption experiment. The results indicated that the adsorption amounts by arborvitae leaves increased sharply from 1.12 to 8.76 mg/g for Pb(II), 0.49 to 3.87 mg/g for Cu(II), and 0.44 to 2.28 for Co(II), respectively, with pH increasing from 1.79 to 4.26. The adsorption equilibrium was attained within 120 min, and the adsorption affinity order of the three heavy metals was Pb > Cu > Co in both of the single and ternary systems. All equilibrium data of Pb(II), Cu(II), and Co(II) ions obtained fit perfectly with Langmuir isotherm model compared with Freundlich isotherm model. Compared with the results in the single system, the adsorption capacity of Pb(II), Cu(II), and Co(II) ions on arborvitae leaves decreased from 35.84 to 9.32 mg/g, 7.94 to 3.07 mg/g, and 6.78 to 1.54 mg/g in the ternary systems, respectively. For the Dubinin–Kaganer–Radushkevich isotherm model, the sorption energy E-values for Pb(II), Cu(II), and Co(II) ions on arborvitae leaves were all below 8 kJ/mol in the single and ternary metal solution systems, indicating that the adsorption mechanism could be explained as the physical adsorption.