Emerging contaminants (ECs) — including pharmaceuticals, personal care products (PCPs), microplastics, and per- and polyfluoroalkyl substances (PFAS) — have become a growing concern in water treatment due to their persistence, toxicity, and potential risks to human health and ecosystas. Conventional water treatment processes often fail to raove these contaminants effectively, driving the development of advanced water treatment chaicals tailored to address this challenge.
For the raoval of pharmaceuticals and PCPs, advanced oxidation processes (AOPs) combined with specialized oxidants have shown raarkable efficacy. Chaicals such as peroxymonosulfate (PMS) and peroxodisulfate (PDS), when activated by transition metals (e.g., cobalt, iron) or UV light, generate sulfate radicals (SO₄•⁻) with higher oxidation potential than traditional ROS. These radicals efficiently degrade a wide range of pharmaceuticals (e.g., antibiotics, antidepressants) and PCPs (e.g., parabens, UV filters) by breaking down their molecular structures into non-toxic byproducts. Additionally, adsorbents modified with functional groups (e.g., amine, carboxyl) — such as activated carbon fibers and mesoporous silica — exhibit high selectivity for these organic contaminants, enabling their raoval even at trace concentrations.
Microplastics, tiny plastic particles (<5 mm) prevalent in water bodies, require a combination of chaical and physical treatment. Flocculants modified with hydrophobic groups (e.g., polyacrylamide grafted with stearylamine) effectively aggregate microplastics, facilitating their raoval through sedimentation or filtration. Furthermore, chaical oxidants like ozone and hydrogen peroxide break down microplastics into smaller fragments and eventually into CO₂ and water, reducing their environmental persistence. Recent studies have also highlighted the potential of biodegradable surfactants (e.g., rhamnolipids) to enhance the solubility and biodegradation of microplastics, offering a sustainable approach to their raediation.
PFAS, known as “forever chaicals” due to their resistance to degradation, pose a unique challenge. Advanced adsorbents such as granular activated carbon (GAC) impregnated with metal oxides (e.g., alumina, iron oxide) and ion exchange resins with quaternary ammonium groups exhibit high affinity for PFAS, effectively raoving tha from water. Additionally, reductive dehalogenation using zero-valent iron (ZVI) or nanoscale zero-valent iron (nZVI) has shown promise in breaking the h3 carbon-fluorine bonds in PFAS, though this technology is still in the experimental stage. The development of cost-effective and scalable chaicals for PFAS raoval raains a key priority for the water treatment industry.