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Environ Sci Pollut Res Int. 2016 Dec;23(23):23606-23618. Epub 2016 Sep 10.

Enhanced adsorption of methylene blue by citric acid modification of biochar derived from water hyacinth (Eichornia crassipes).

Xu Y1,2, Liu Y3,4, Liu S5,6, Tan X1,2, Zeng G1,2, Zeng W1,2, Ding Y1,2, Cao W1,2, Zheng B7.

Author information

1
College of Environmental Science and Engineering, Hunan University, Changsha, 410082, People's Republic of China.
2
Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, People's Republic of China.
3
College of Environmental Science and Engineering, Hunan University, Changsha, 410082, People's Republic of China. liuyunguo2012@yeah.net.
4
Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, People's Republic of China. liuyunguo2012@yeah.net.
5
School of Metallurgy and Environmental, Central South University, Changsha, 410083, People's Republic of China. 15171352964@163.com.
6
School of Architecture and Art, Central South University, Changsha, 410082, People's Republic of China. 15171352964@163.com.
7
School of Architecture and Art, Central South University, Changsha, 410082, People's Republic of China.

Abstract

In this work, a novel potential adsorbent, citric acid (CA)-modified biochar, named as CAWB, was obtained from water hyacinth biomass by slow pyrolysis in a N2 environment at 300 °C. The CA modification focused on enhancing the contaminants adsorption capacity of biochar pyrolyzed at relatively low temperature. Over 90 % of the total methylene blue (MB) could be removed at the first 60 min by CAWB, and the maximum MB adsorption capacity could reach to 395 mg g-1. The physicochemical properties of CAWB was examined by FTIR, XPS, SEM, and BET analysis. The results indicated that the additional carboxyl groups were introduced to the surface of CAWB via the esterification reaction with CA, which played a significant role in the adsorption of MB. Batch adsorption studies showed that the initial MB concentration, solution pH, background ionic strength, and temperature could affect the removal efficiency obviously. The adsorption process could be well described by the pseudo-second-order kinetic model and Langmuir isotherm. Thermodynamic analysis revealed that the MB adsorption onto CAWB was an endothermic and spontaneous process. The regeneration study revealed that CAWB still exhibited an excellent regeneration and adsorption performance after multiple cycle adsorptions. The adsorption experiments of actual dye wastewater by CAWB suggested that it had a great potential in environmental application.

KEYWORDS:

Adsorption; Biochar; Citric acid; Dye wastewater; Modification; Water hyacinth

PMID:
27614648
DOI:
10.1007/s11356-016-7572-6
[Indexed for MEDLINE]

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