UV-TiO2 particles interacting with water contaminants

The UV-TiO2 Breakthrough: Is This the Key to Cleaner Water?

Lena Voss in Climate & Environment August 2025 • 4 min read.

"Discover how UV-TiO2 pretreatment is revolutionizing water filtration, making it easier and more effective than ever before."

In a world increasingly aware of the importance of clean water, scientists and engineers are constantly seeking new and improved methods of water treatment. One area of particular interest is ultrafiltration (UF), a process used to remove natural organic matter (NOM) from water. While UF is effective, it can be hampered by membrane fouling, a phenomenon where contaminants accumulate on the membrane surface, reducing its efficiency. This is where a promising innovation comes into play: UV-TiO2 pretreatment.

A recent study published in the Chemical Engineering Journal explores the use of UV-TiO2 pretreatment to combat membrane fouling in ceramic UF membranes. The study investigates how this pretreatment affects the mechanisms of fouling development, providing valuable insights into creating more effective water filtration systems. The target audience can relate to the need of clean water and the problem of water scarcity.

The research focuses on the impact of UV-TiO2 photocatalysis as a pretreatment method to lessen the effects of humic acid (HA), a major culprit in membrane fouling. By understanding how UV-TiO2 interacts with HA, researchers aim to unlock new strategies for keeping UF membranes clean and functioning at their best.

Unlocking the Science Behind UV-TiO2 Pretreatment

UV-TiO2 particles interacting with water contaminants

The study meticulously examined how UV-TiO2 pretreatment affects various characteristics of organic matter in water, including dissolved organic carbon (DOC), specific ultraviolet absorbance (SUVA), and molecular weight (MW). Researchers also looked at hydrophilicity, fouling resistance, and the physical structure of the membrane surface using scanning electron microscopy (SEM).

The dominant membrane fouling patterns can be predicted by initial intermediate pore blocking, transition fouling, and the final stage of limited cake growth. Extended UV-TiO2 pretreatment time resulted in a significant reduction of cake filtration coefficients and a slight decrease in pore blocking coefficients was observed. Longer UV/TiO2 pretreatment achieved the remarkable effect of reversible fouling elimination as a result of reaching the final stage of limited cake growth earlier.

Here are the main benefits of UV-TiO2 pretreatment:

Reduces cake filtration coefficients
Decreases pore blocking
Enhances reversible fouling elimination
Promotes a more porous cake layer

According to the research, UV-TiO2 pretreatment works by transforming hydrophobic (water-repelling) organic compounds into hydrophilic (water-attracting) ones. This change makes it harder for foulants to stick to the membrane surface. The researchers found that photocatalytic pretreatment had a slight effect on the mitigation of irreversible fouling that was mainly dominated by HPI fractions, especially tryptophan-like protein (5–50 kDa) organics attaching to and/or blocking the membrane pores.

A Promising Future for Clean Water

The findings of this study suggest that UV-TiO2 pretreatment holds significant promise as a strategy for reducing membrane fouling and improving the efficiency of ultrafiltration processes. By pretreating water with UV-TiO2, filtration systems can operate more effectively, providing cleaner and safer water for various uses. Further research and development in this area could pave the way for more sustainable and cost-effective water treatment solutions in the future.

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This article is based on research published under:

DOI-LINK: 10.1016/j.cej.2018.10.149, Alternate LINK

Title: Effect Of Uv/Tio2 Pretreatment On Fouling Alleviation And Mechanisms Of Fouling Development In A Cross-Flow Filtration Process Using A Ceramic Uf Membrane

Subject: Industrial and Manufacturing Engineering

Journal: Chemical Engineering Journal

Publisher: Elsevier BV

Authors: Tao Yang, Houfeng Xiong, Fen Liu, Qiyong Yang, Bingjie Xu, Changchao Zhan

Published: 2019-02-01

Everything You Need To Know

What is UV-TiO2 pretreatment and how does it enhance water filtration?

UV-TiO2 pretreatment is an innovative method used to enhance water filtration processes, specifically targeting the issue of membrane fouling in ultrafiltration (UF). It involves using ultraviolet (UV) light in combination with titanium dioxide (TiO2) to pretreat water before it undergoes ultrafiltration. This pretreatment helps in reducing the accumulation of contaminants on the membrane surface, thereby improving the efficiency and effectiveness of the filtration process. By modifying the properties of organic matter in the water, UV-TiO2 pretreatment makes it more difficult for foulants to adhere to the membrane, leading to a more sustainable solution for obtaining cleaner and safer water.

How does UV-TiO2 pretreatment specifically combat membrane fouling caused by humic acid (HA) during ultrafiltration (UF)?

Membrane fouling, particularly caused by humic acid (HA), reduces the efficiency of ultrafiltration (UF) membranes by accumulating contaminants on the membrane surface. UV-TiO2 pretreatment addresses this issue by using UV-TiO2 photocatalysis to lessen the effects of humic acid. The process transforms hydrophobic organic compounds into hydrophilic ones, making it harder for these compounds to stick to the membrane surface. This reduces the formation of a dense cake layer, promotes a more porous cake layer, decreases pore blocking, and enhances reversible fouling elimination. Further research is needed to optimize the process for different types of organic matter and membrane materials.

What characteristics of organic matter in water are affected by UV-TiO2 pretreatment, and how are these changes measured?

UV-TiO2 pretreatment influences several key characteristics of organic matter in water. It leads to changes in dissolved organic carbon (DOC), specific ultraviolet absorbance (SUVA), and molecular weight (MW). Furthermore, it impacts hydrophilicity, converting hydrophobic compounds into hydrophilic ones, and enhances fouling resistance. Scanning electron microscopy (SEM) is used to examine changes in the physical structure of the membrane surface, revealing a more porous cake layer. The interplay of these factors contributes to the reduction of membrane fouling and improvement of ultrafiltration efficiency.

How does UV-TiO2 pretreatment time affect membrane fouling patterns, and what are the implications for ultrafiltration system performance?

The study identifies initial intermediate pore blocking, transition fouling, and the final stage of limited cake growth as the dominant membrane fouling patterns. Extended UV-TiO2 pretreatment time leads to a significant reduction of cake filtration coefficients and a slight decrease in pore blocking coefficients. Longer UV/TiO2 pretreatment enables reversible fouling elimination to occur earlier because the system reaches the final stage of limited cake growth faster. The implications are that optimizing UV-TiO2 pretreatment duration can significantly improve the longevity and efficiency of ultrafiltration membranes, decreasing maintenance needs and operational costs.

Does UV-TiO2 pretreatment address all types of membrane fouling, and what are its limitations regarding irreversible fouling?

While UV-TiO2 pretreatment has shown promise in mitigating reversible fouling, research indicates it has a limited effect on irreversible fouling, which is primarily dominated by HPI fractions, especially tryptophan-like protein (5–50 kDa) organics that attach to and/or block the membrane pores. This suggests that additional pretreatment methods or modifications to the UV-TiO2 process may be necessary to address irreversible fouling effectively. Future studies could focus on combining UV-TiO2 with other advanced oxidation processes or optimizing the pretreatment conditions to target these specific organic fractions, thereby further enhancing the overall performance of ultrafiltration systems.