1. H2O2 modified-hydrochar derived from paper waste sludge for enriched surface functional groups and promoted adsorption to ammonium.
- Author
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Nguyen, Lan Huong, Nguyen, Xuan Hoan, Nguyen, Ngoc Dang Khoa, Van, Huu Tap, Thai, Van Nam, Le, Hoang Nghiem, Pham, Van Dat, Nguyen, Ngoc Anh, Nguyen, Tan Phong, and Nguyen, The Hung
- Subjects
WASTE paper ,FUNCTIONAL groups ,WATER treatment plant residuals ,ADSORPTION (Chemistry) ,ADSORPTION isotherms ,SURFACE chemistry - Abstract
• H 2 O 2 modification of hydrochar increased surface functional groups on hydrochar. • Modified hydrochar adsorbed NH 4
+ better than pristine hydrochar by two times. • NH 4+ adsorption was mainly controlled by cation exchange and electrostatic attraction. • Modified hydrochar can be used as a promising alternative adsorbent for NH 4+ removal. This work investigated adsorption behaviors of NH 4+ onto H 2 O 2 modified paper waste sludge-derived hydrochar (HPSH). Effect of various operational parameters, including modification ratio, solution pH, adsorbent dosage, initial NH 4+ concentration and contact time on NH 4+ adsorption was studied. Besides, the NH 4+ adsorption isotherms, kinetics and thermodynamics at different operational temperatures were systematically investigated. The textural, morphology, crystalline structure and surface chemistry characteristics of hydrochars were analyzed. Specially, NH 4+ adsorption mechanisms controlled by enriched oxygen-containing surface functional groups by treatment of H 2 O 2 onto hydrochars were deeply discussed. The results showed that the optimal treatment ratio between H 2 O 2 and PPSH was 40. Characterization data indicated H 2 O 2 modification increased the oxygen-containing functional groups on the hydrochar surface. The maximum adsorption capacity of HPSH-40 was 7.941 mg/g which was higher that of PPSH about double. NH 4+ adsorption onto hydrochars was well described by the pseudo-second-order model and Langmuir isotherm. The thermodynamic studies showed NH 4+ adsorption onto hydrochars was endothermic in nature. The mechanisms of NH 4+ adsorption onto hydrochars included π-cation interaction, cation exchange, surface complexation and electrostatic attraction which were attributed to the vital role of enriched oxygen-containing surface functional groups on hydrochar's surface. [Display omitted] [ABSTRACT FROM AUTHOR]- Published
- 2021
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