A Valuable Biochar from Poplar Catkins with High Adsorption Capacity for Both Organic Pollutants and Inorganic Heavy Metal Ions

Xia Liu,Chengming Wang,Jiaxing Li,Ju Sun,Tasawar Hayat,Yanan Wang,Ahmed Alsaedi,Shengxia Duan

doi:10.1038/s41598-017-09446-0

Abstract

In this paper, biochar derived from poplar catkins was used as an economical and renewable adsorbent for adsorption organic and inorganic pollutants such as, dyes, organic compounds, and heavy metal ions from wastewater. Mesoporous activated carbonized poplar catkins (ACPCs) were produced from char as a by-product by carbonized poplar catkins (CPCs). With their high surface area, ACPCs exhibited the maximum adsorption capacities of 71.85 and 110.17 mg/g for the removal of inorganic U(VI) and Co(II). Compared other biochars adsorbents, ACPCs can also adsorb organic pollutants with the maximum adsorption capacities of 534, 154, 350, 148 and 384 mg/g for methylene blue (MB), methyl orange (MO), Congo red (CR), chloramphenicol (CAP) and naphthalene. The adsorption of organic pollutants was fitted with pseudo-first order, pseudo-second order, and intra-particle diffusion kinetic models figure out the kinetic parameters and adsorption mechanisms. Langmuir adsorption isotherm was found to be suitable for Co(II) and U(VI) adsorption and thermodynamic studies indicated adsorption processes to be endothermic and spontaneous. The adsorption process includes both outer-sphere surface complexes and hydrogen-bonding interactions. The results showed that biochar derived from poplar catkins was a potential material to remove pollutants in wastewater.

Highlights

The morphologies of carbonized poplar catkins (CPCs) and activated carbonized poplar catkins (ACPCs) were characterized by using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis
The CPCs samples showed hollow micro-tubular structure with the thin layers[24, 25] (Fig. 1A) while the SEM image of ACPCs (Fig. 1B) displayed a network and porous structure stacked by irregular flakes, which could be considered as high specific surface area
The TEM image of CPCs (Fig. 1C) confirmed its hollow micro-tubular structure while ACPCs (Fig. 1D) were network structure stacked by irregular flakes

Summary

Pollutants and Inorganic Heavy Metal Ions

Xia Liu[1,2], Ju Sun[1,2], Shengxia Duan[1,2], Yanan Wang[1,2], Tasawar Hayat[4], Ahmed Alsaedi[4,5], Chengming Wang2 & Jiaxing Li1,3,4. Biochar derived from poplar catkins was used as an economical and renewable adsorbent for adsorption organic and inorganic pollutants such as, dyes, organic compounds, and heavy metal ions from wastewater. Mesoporous activated carbonized poplar catkins (ACPCs) were produced from char as a by-product by carbonized poplar catkins (CPCs) With their high surface area, ACPCs exhibited the maximum adsorption capacities of 71.85 and 110.17 mg/g for the removal of inorganic U(VI) and Co(II). A number of effective techniques including adsorption, filtration and ion exchange, have been applied to remove inorganic and organic pollutants from waste solutions[9,10,11] Among these techniques, adsorption has become one of the most widely used techniques for water pollution management due to its outstanding characteristics, such as low cost, wide adaptability, and convenience[12]. The possible adsorption mechanism of the pollutants was investigated through FT-IR analysis

Results and Discussion

This work

Freundlich model

Author Contributions

Additional Information