A team of Yale researchers has recently developed a more efficient process of catalyzing hydrogen peroxide (H2O2), a compound used in medicine, chemical synthesis, and yes, rocket fuel. The team of researchers are using H2O2 as a safer water purification chemical, as opposed to traditionally used chlorine. “Nearly a third of the population worldwide is estimated to lack access to safely managed drinking water,” reports a study conducted by Yale researchers Dr. Jaehong Kim, Professor Ezra Cates, and Brenna Hodges in the scientific magazine Nature Nanotechnology. Although the issue of access to clean water typically only affects developing countries, problems in our own water treatment systems are beginning to cause alarm. Our centralized method of purifying water is running into challenges due to aging infrastructure, a growing population, and a host of other factors.
Scientists are now looking at a more decentralized, energy efficient, and cost-effective method of decontaminating water. This alternative method utilizes advanced oxidation processes (AOPs). An AOP is a chemical treatment procedure intended to remove pollutants in water by oxidation through reactions with hydroxyl radicals. In water-treatment, this process utilizes the chemical compound hydrogen peroxide. “In environmental remediation, we add hydrogen peroxide to contaminated water and activate the oxidant. This activation breaks down hydrogen peroxide into a radical.” A metal (being used as a catalyst) and H2O2 are combined in a method known as the Fenton process to generate these highly reactive hydroxyl radicals, which in turn “destroy everything in the water thus ridding it of contaminants” says Dr. Kim. Additionally, H2O2 is safe and environmentally friendly since it generates only water and oxygen following its use.
The problem with AOPs and H2O2 synthesis is that they require a considerable amount of chemical input and energy. Luckily, recent advances in nanotechnology have prompted greater research into engineered nanomaterials (ENM) and how they can combat the challenges facing AOPs. ENMs are extremely small chemical substances or materials that can potentially be used as catalysts given their unique physiochemical and electrical properties and hopefully accelerate H2O2 synthesis. The Kim research group at Yale has found an approach to accelerate H2O2 production by “tuning” palladium nanoparticles to increase their density, thereby increasing H2O2 production. “Tuning” refers to the process of “tailoring the architecture and physicochemical properties of metallic nanoparticles” using “organic ligands.” This process manipulates, “the electronic environment of metallic nanoparticles to optimize their catalytic performance.” The results from this new innovative method are promising, and “electronically tuned palladium nanoparticles achieve an unprecedented efficiency for photocatalytic H2O2 production, using water, oxygen, and sunlight as the only chemical and energy inputs.” Current H2O2 synthesis methods produce high amounts of CO2, so this improved method of production will be a safer and greener way of creating the compound and can possibly greatly improve the process of purifying water worldwide. Dr. Kim is highly optimistic about the future and hopes to use his research not only for the purposes of water-treatment, but also for pharmaceuticals and medical treatment.