With the large-scale development of the livestock industry, a substantial amount of high-concentration organic wastewater is generated. Pollutants such as residual antibiotics, pharmaceutical ingredients, and heavy metals in the wastewater pose a serious threat to the safety of the water environment. Traditional physical adsorption and biological treatment methods are difficult to completely degrade these refractory organic substances and may even cause secondary pollution. Against this background, photocatalytic oxidation technology, as an efficient and clean new treatment method, has gradually attracted the attention of researchers. It uses light energy to excite catalysts, generating highly oxidizing free radicals that completely decompose organic pollutants into harmless water and carbon dioxide. However, despite its great potential, this technology has not yet been widely applied in practical wastewater treatment. So, what exactly limits its promotion?
Recently, Professor Fenwu Liu and Associate Professor Qingjie Hou from the College of Resource and Environment, Shanxi Agricultural University, systematically explored this issue in a review article. The article points out that the core bottlenecks of photocatalytic technology lie in the extremely low utilization rate of visible light in sunlight by commonly used catalysts (such as titanium dioxide and zinc oxide), the fast recombination rate of carriers, and the difficulty in recycling nanomaterials. These factors lead to low catalytic efficiency and increased costs, restricting its application in practical engineering. The article has been published in Frontiers of Agricultural Science and Engineering (DOI: 10.15302/J-FASE-2025656).
To break through these limitations, researchers have attempted to start with material modification. For example, regulating the morphology of catalysts, reducing particle size, and increasing specific surface area can effectively enhance light absorption and utilization, and improve reaction activity. In addition, methods such as element doping (introduction of metal ions or non-metallic elements), noble metal deposition, and construction of heterojunction composite materials have also been proven to significantly expand the visible light response range of catalysts and delay the recombination of electron-hole pairs, thereby improving degradation efficiency.
Many studies have begun to focus on the sustainability and economy of materials. For instance, modifying catalysts using useful components from solid waste not only reduces raw material costs but also realizes resource recycling. In addition, some non-noble metal materials (such as copper and molybdenum) have been explored as alternatives to expensive noble metals, showing good catalytic potential and cost advantages.
However, the article also points out that most current studies are still in the laboratory stage, using simulated light sources and single-pollutant systems, which are quite different from the complex composition of actual wastewater and natural light conditions. Various pollutants, electrolytes, and other inhibitors in wastewater can affect the photocatalytic effect, and the instability of natural light also puts forward higher requirements for the practical application of the technology.
Looking forward to the future, promoting the practicalization of photocatalytic oxidation technology requires more attention to evaluating material performance under real environmental conditions, and developing green synthesis pathways with low temperature and low energy consumption, so as to promote the large-scale application of this technology in the treatment of livestock and poultry breeding wastewater.
DOI:10.15302/J-FASE-2025656