Na@La-modified zeolite particles for simultaneous removal of ammonia nitrogen and phosphate from rejected water: performance and mechanism

Rejected water from sludge processing in wastewater treatment plants (WWTPs) is very harmful due to its high concentration of ammonia nitrogen and phosphorus. It is therefore necessary to find a low-cost and convenient technique to simultaneously remove ammonia nitrogen and phosphorus from rejected...

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Bibliographic Details
Published in:Water science and technology 2020-12, Vol.82 (12), p.2975-2989
Main Authors: Sang, Wenjiao, Mei, Longjie, Hao, Shiwen, Li, Dong, Li, Xiaoyang, Zhang, Qian, Jin, Xi, Li, Cuihua
Format: Article
Language:English
Subjects:
Adsorbents
Adsorption
Ammonia
Chemical reactions
China
Composite materials
Effluent standards
Experiments
Kinetics
Metal oxides
Nitrogen
Phosphates
Phosphorus
Reaction time
Removal
Sludge
Sodium chloride
Waste Water
Wastewater treatment
Wastewater treatment plants
Water
Water Pollutants, Chemical
Water treatment
Zeolites
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Summary:Rejected water from sludge processing in wastewater treatment plants (WWTPs) is very harmful due to its high concentration of ammonia nitrogen and phosphorus. It is therefore necessary to find a low-cost and convenient technique to simultaneously remove ammonia nitrogen and phosphorus from rejected water. In this study, natural granular zeolite was modified by NaCl and La(OH) to obtain a new material (Na@La-MZP), with several advantages compared with powdered zeolite. Na@La-MZP could remove 92.61% ammonia nitrogen (50 mg/L) and 99.01% phosphate (60 mg/L) at the optimal conditions of dosage 12.5 g/L, initial pH 6.0 and reaction time 12 hours, which enabled the effluent to satisfy the discharge standard (GB 18918-2002) for municipal WWTPs in China. The maximum adsorption capacity of Na@La-MZP was determined as 17.92 mg NH -N/g and 9.53 mg P/g by the Langmuir isotherm. Pseudo-second-order kinetics could well illustrate the adsorption process and show that the ammonia nitrogen and phosphate can be degraded by chemical reaction. The characterizations of Na@La-MZP confirmed the removal mechanism of ammonia nitrogen and phosphate. The Na@La-MZP still maintained more than 75% removal efficiency after five reuses. Furthermore, the estimated cost of this treatment method was 0.22 $/m rejected water.
ISSN:0273-1223
1996-9732
DOI:10.2166/wst.2020.541