Impact of silica-alumina ratio on ammonium adsorption by molecular sieves - Details

Author：

Liu, Si-Yuan (Liu, Si-Yuan.) | Hao, Rui-Xia (Hao, Rui-Xia.) | Liu, Hang (Liu, Hang.) | Wang, Li-Sha (Wang, Li-Sha.) | Li, Jia-Wen (Li, Jia-Wen.)

Indexed by：

EI PKU CSCD

Abstract：

This　study　examined　the　difference　of　ammonium　adsorption　by　molecular　sieve　with　different　silica-alumina　ratios　that　were　determined　using　x-rays　fluorescence　(XRF)　method.　Based　on　the　results　from　scanning　electron　microscopy　(SEM)　and　X-ray　diffraction　(XRF),　It　was　investigated　the　adsorption　mechanism　of　molecular　sieve　under　different　silica-alumina　ratio　conditions　from　the　perspective　of　molecular　sieve　framework,　surface　morphology,　and　crystal　structure.　Meanwhile,　the　ammonium　adsorption　improvement　through　the　desilicification　of　molecular　sieve　framework　was　revealed,　and　this　would　provide　technical　reference　for　the　molecular　sieve　based　deep　denitrification　of　sewage　treatment　plant　effluent.　The　results　indicated　that　molecular　sieves　with　different　silica-alumina　ratio　had　significant　variation　in　surface　morphology,　crystal　structure,　and　ammonium　adsorption　performance.　It　was　found　that　the　increased　silica-alumina　ratio　was　associated　with　decreased　crystallization,　increased　obscuring　of　crystal　grain　shape,　and　decreased　adsorption　capacity.　When　the　silica-alumina　ratio　rose　from　35　to　237,　the　equilibrium　adsorption　capacity　of　ammonium　by　molecular　sieve　decreased　from　5.65mg/g　to　0.41mg/g,　and　the　monolayer　adsorption　saturation　capacity　confirmed　by　Langmuir　adsorption　isotherm　decreased　from　6.5963mg/g　to　0.4430mg/g.　The　adsorption　process　conformed　to　the　pseudo-second-order　kinetic　model,　which　was　revealed　that　the　adsorption　rate　was　controlled　by　the　mechanism　of　ion-exchange　chemical　adsorption.　Both　the　ion-exchange　capacity　of　molecular　sieve　and　the　rate　of　adsorption　decreased　with　the　increase　in　silica-alumina　ratio.　It　was　observed　that　the　ability　of　ammonium　absorption　was　significantly　improved　by　desilicification　process　of　molecular　sieve　framework,　and　the　equilibrium　ammonium　adsorption　with　a　silica-alumina　ratio　of　35increased　by　81.6%　after　a　desilicification　process.　This　would　provide　an　effective　technological　approach　for　improving　the　ammonium　adsorption　by　molecular　sieve.　©　2019,　Editorial　Board　of　China　Environmental　Science.　All　right　reserved.

Keyword：

Morphology Alumina Effluents Ion exchange Silica Sieves Aluminum oxide Monolayers Surface morphology Sewage treatment plants Crystal structure Molecular sieves Effluent treatment Scanning electron microscopy Adsorption

Author Community：

[ 1 ] [Liu, Si-Yuan]Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, College of Architectural Engineering, Beijing University of Technology, Beijing; 100124, China
[ 2 ] [Hao, Rui-Xia]Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, College of Architectural Engineering, Beijing University of Technology, Beijing; 100124, China
[ 3 ] [Liu, Hang]Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, College of Architectural Engineering, Beijing University of Technology, Beijing; 100124, China
[ 4 ] [Wang, Li-Sha]Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, College of Architectural Engineering, Beijing University of Technology, Beijing; 100124, China
[ 5 ] [Li, Jia-Wen]Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, College of Architectural Engineering, Beijing University of Technology, Beijing; 100124, China

Reprint Author's Address：

[hao, rui-xia]key laboratory of beijing for water quality science and water environment recovery engineering, college of architectural engineering, beijing university of technology, beijing; 100124, china

Email：

haoruixia@bjut.edu.cn

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