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Hydrogels as metal ions adsorbents are commonly applied in wastewater treatment field. However, low swelling ratio (SR) of ever reported hydrogel adsorbents prevents adsorptive sites from effectively exposing to metal ions, leading to unpleasant removal efficiency for trace metal ions. Designing high SR for hydrogel adsorbents can increase contact area between adsorbents and metal ions, being favorable for the internal adsorption sites exposure to metal ions. Thus, improved adsorption performance for removing trace metal ions can be achieved by endowing high SR for hydrogel adsorbents. In the present work, poly(acrylic acid) hydrogel adsorbent achieves high SR up to 8130 g/g by employing calcium hydroxide (Ca(OH)2) nano-spherulites as cross-linkers, which can effectively adsorb various trace metal ions including Cu2+, Cd2+, Cr6+, Fe3+, Mn2+, Ni2+, Zn2+, Ce3+ and Ag+. The removal ratios reach 46.8% for Cu2+ (initial concentration C0 = 0.16 mg/L), 57.1% for Cd2+ (C0 = 0.56 mg/L), 26.9% for Cr6+ (C0 = 0.52 mg/L), 5.3% for Fe3+ (C0 = 0.56 mg/L), 52.7% for Mn2+ (C0 = 0.55 mg/L), 52.5% for Ni2+ (C0 = 0.59 mg/L), 58.4% for Zn2+ (C0 = 0.65 mg/L), 70% for Ce3+ (C0 = 0.7 mg/L) and 45.3% for Ag+ (C0 = 1.08 mg/L) by using such adsorbent, respectively. This work develops a potential hydrogel adsorbent for the efficient removal of trace metal ions. Keywords: Hydrogel, Metal ions, Adsorption, Wastewater

This paper evaluates potential of a novel, low-cost, and environmental friendly cement-based composite for wind energy harvesting. The composite is fabricated of cementitious matrix. Fibers and mesh reinforcements were introduced into the matrix for enhanced flexural performance. The composite was used to fabricate wind turbine blades which were tested for suitability under varying wind loadings. Wind turbine blades fabricated of the proposed cementitious composite successfully yielded power output when tested in wind tunnel; the maximum power coefficient being 0.182. The developed composite was also tested for mechanical performance and early-age shrinkage, the results of which indicated satisfactory performance. The proposed composite, if used for fabricating wind turbine blades, can significantly reduce the wind power generation cost. However, the lower power coefficient attained in this study can be improved by using hollow cross sections which are anticipated to reduce the corresponding unit weight and augment aerodynamic behavior of blades. Keywords: Lightweight, Cementitious composite, Wind energy harvesting, Laminated composite

Mechanically strong poly(acrylamide) nanocomposite hydrogels (NC gels), reinforced by calcium hydroxide nano-spherulites (CNS) with diameter