title: A facile, versatile approach to hydroxyl-anchored metal oxides with high Cr(VI) adsorption performance in water treatment.
abstract: In this study, a facile and versatile urea-assisted approach was proposed to synthesize Chinese rose-like NiO, pinecone-like ZnO and sponge-like CoO adsorbents. The presence of urea during syntheses endowed these adsorbents with high concentration of surface hydroxyl groups, which was estimated as 1.83, 1.32 and 4.19 mmol [OH-] g-1for NiO, ZnO and CoO adsorbents, respectively. These surface hydroxyl groups would facilitate the adsorption of Cr(vi) species (e.g. HCrO4-, Cr2O72-and CrO42-) from wastewater by exchanging with hydroxyl protons or hydroxide ions, and hence result in extremely high maximum adsorbed amounts of Cr(vi), being 2974, 14 256 and 408 mg g-1for NiO, ZnO and CoO adsorbents in the pH range of 5.02-5.66 at 298 K, respectively. More strikingly, the maximum adsorbed amounts of Cr(vi) would be greatly enhanced as the adsorbing temperature is increased, and even amount to 23 411 mg g-1for ZnO adsorbents at 323 K. Based on the kinetics and equilibrium studies of adsorptive removal of Cr(vi) from wastewater, our synthetic route will greatly improve the adsorptivity of the as-synthesized metal-oxide adsorbents, and hence it will shed new light on the development of high-performance adsorbents.
authors.affiliation: Lab of Functional and Biomedical Nanomaterials, College of Materials Science and Engineering , Qingdao University of Science and Technology , No. 53 Zhengzhou Road, Qingdao 266042 , People's Republic of China.
authors.forename: Ji
authors.initials: J
authors.lastname: Ma
authors.affiliation: Lab of Functional and Biomedical Nanomaterials, College of Materials Science and Engineering , Qingdao University of Science and Technology , No. 53 Zhengzhou Road, Qingdao 266042 , People's Republic of China.
authors.forename: SiZhi
authors.initials: S
authors.lastname: Zuo-Jiang
authors.affiliation: Lab of Functional and Biomedical Nanomaterials, College of Materials Science and Engineering , Qingdao University of Science and Technology , No. 53 Zhengzhou Road, Qingdao 266042 , People's Republic of China.
authors.forename: Yunhao
authors.initials: Y
authors.lastname: He
authors.affiliation: Lab of Functional and Biomedical Nanomaterials, College of Materials Science and Engineering , Qingdao University of Science and Technology , No. 53 Zhengzhou Road, Qingdao 266042 , People's Republic of China.
authors.forename: Qinglei
authors.initials: Q
authors.lastname: Sun
authors.affiliation: Lab of Functional and Biomedical Nanomaterials, College of Materials Science and Engineering , Qingdao University of Science and Technology , No. 53 Zhengzhou Road, Qingdao 266042 , People's Republic of China.
authors.forename: Yunguo
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Lab of Functional and Biomedical Nanomaterials, College of Materials Science and Engineering , Qingdao University of Science and Technology , No. 53 Zhengzhou Road, Qingdao 266042 , People's Republic of China.
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.affiliation: Lab of Functional and Biomedical Nanomaterials, College of Materials Science and Engineering , Qingdao University of Science and Technology , No. 53 Zhengzhou Road, Qingdao 266042 , People's Republic of China.
authors.forename: Shuangshuang
authors.initials: S
authors.lastname: Sun
authors.affiliation: Lab of Functional and Biomedical Nanomaterials, College of Materials Science and Engineering , Qingdao University of Science and Technology , No. 53 Zhengzhou Road, Qingdao 266042 , People's Republic of China.
authors.forename: Kezheng
authors.identifier: 0000-0001-6659-2078
authors.initials: K
authors.lastname: Chen
keywords: adsorption; chromium; metal oxides; water treatment