Investigation of utilizing carbonized lotus root as photothermal material in the solar steam generation system

ABSTRACT

It is well-known that the shortage of water resources is one of the most serious global challenges. Steam generation via the solar system is one of the effective alternative ways that received significant interest in the last years to obtain clean water. Photothermal materials have received particular interest in this field; however, they suffer drawbacks, mainly high cost and poor energy efficiency, durability, and salt resistance. In this study, we selected carbonized lotus root as an alternative cheap photothermal material-hydrophilic functional groups with complete and abundant channels via freeze-drying technology. The carbonized lotus root has been prepared at different temperatures, and its ability in steam production has been investigated. The steam generation from seawater and with various NaCl added ratios has been examined via a solar simulator. The results showed that carbonized lotus root prepared at 900°C has a three-dimensional porous structure, high photothermal conversion efficiency, and evaporation performance in seawater and salt solution. The water evaporation rates for pure water, 1.4% NaCl, and 4.1% NaCl solutions are 0.90, 0.85, and 0.83 kg m⁻² h⁻¹, respectively. The ratio of the photothermal conversion is 61.3%, 58%, and 56% under 1 kW m⁻² illumination. It has a certain guiding significance for the subsequent practical application.

KEYWORDS:

• Photothermal conversion
• Biomass carbon material
• Lotus root
• Solar steam generation
• Energy conversion efficiency

Acknowledgements

This work is financially supported by the National Natural Science Foundation of China (No. 21676148) and Tianjin Research Innovation Project for Postgraduate Students (No. 2019KJ149)

Disclosure statement

No potential conflict of interest was reported by the authors.

Data availability statement

Data will be made available under reasonable request.

Additional information

Funding

The work was supported by the National Natural Science Foundation of China [21676148]; Tianjin Research Innovation Project for Postgraduate Students [2019KJ149]

Notes on contributors

La Zhang

La Zhang is a teacher of Department of energy Engineering, focusing on the energy conversion.

Changchang Sha

Changchang Sha is a student of Nanjing university of Science and Technology, focusing on the carbon materials.

Bingbing Li

Bingbing Li is a teacher of Tianjin Renai college, focusing on materials design and application.

Wenju Wang

Wenju Wang is a teacher of Nanjing University of Science and Technology, focusing on energy storage device and rechargable battery.