Carbonaceous Materials‐Based Photothermal Process in Water Treatment: From Originals to Frontier Applications

Abstract

The photothermal process has attracted considerable attention in water treatment due to its advantages of low energy consumption and high efficiency. In this respect, photothermal materials play a crucial role in the photothermal process. Particularly, carbonaceous materials have emerged as promising candidates for this process because of exceptional photothermal performance. While previous research on carbonaceous materials has primarily focused on photothermal evaporation and sterilization, there is now a growing interest in exploring the potential of photothermal effect‐assisted advanced oxidation processes (AOPs). However, the underlying mechanism of the photothermal effect assisted by carbonaceous materials remains unclear. This review aims to provide a comprehensive review of the photothermal process of carbonaceous materials in water treatment. It begins by introducing the photothermal properties of carbonaceous materials, followed by a discussion on strategies for enhancing these properties. Then, the application of carbonaceous materials‐based photothermal process for water treatment is summarized. This includes both direct photothermal processes such as photothermal evaporation and sterilization, as well as indirect photothermal processes that assisted AOPs. Meanwhile, various mechanisms assisted by the photothermal effect are summarized. Finally, the challenges and opportunities of using carbonaceous materials‐based photothermal processes for water treatment are proposed.

Cost Effective Photothermal Materials Selection for Direct Solar-Driven Evaporation

“…These variations are attributed to the presence of surface groups and π-conjugated structures in their carbon cores . Notably, graphene exhibits exceptional light absorption capabilities, absorbing 2.3% of light across a wide spectrum due to its unique electronic structure known as “Dirac cones.” , For comparison, plasmonic localized heating occurs when these nanomaterials absorb light, leading to the conversion of light energy into heat via plasmonic oscillations of free electrons. , Similarly, in semiconductor materials, nonradiative relaxation takes place as absorbed photons generate electron–hole pairs, with the excess energy dissipating as heat through nonradiative pathways instead of being emitted as light . In contrast, thermal vibration in molecules, observed in carbonaceous and organic polymer materials, is triggered by the absorption of light energy, prompting the atoms within the molecules to vibrate and produce heat due to frictional forces .…”