Environment

The rapid economic growth and technology advancement result in higher quality of human lives. However, what follow as well are various impacts on the surrounding environment. Global warming and air pollution, for instance, are the consequences of human’s over-exploitation of non-renewable energy and those of polluting human activities like large-scaled industrial manufacturing and vehicle emissions. Every year millions metric tons of hazardous wastes are generated, seriously threatening public health and the environment. The threats suggested above are not, nevertheless, inevitable evilness appeared during the process of society development. With modern chemical technology, the impacts of such threats can virtually be minimized.

Waste treatment and reduction

With more advanced technologies and a rapidly expanding population, the volume of man-made waste has increased drastically, and the trend is expected to continue in the future. Electronic waste and synthetic polymers have attracted the most concern amongst solid waste owing to their high toxicity and persistent nature. In the meantime, industrial processes generated much wastewater that must be treated before release. To address the pollution associated with the rapid development, researchers are seeking new methods for waste treatment.

Recent research directions

Recycling precious metals in batteries by water-based processing link

By replacing the binder used in the cathode and anode in lithium-ion batteries, researchers have reported that the production of batteries and recycling the precious metals in electrodes can be done by water-based processing, which avoids the use of a toxic and expensive solvent, N-methyl-2-pyrrolidone (NMP).

Extracting precious metals from waste electronics with the aid of UV radiation link

Researchers developed a simple method to extract precious metals from waste electronics. Upon UV radiation, metals are oxidized and dissolved in a solution of titanium dioxide in acetonitrile in the presence of oxygen. The precious metals can then be recovered in high purity by subsequent reduction.

Decomposition of non-biodegradable plastics using a vanadium-based catalyst link

Non-biodegradable plastics were reported to be decomposed upon excitation of visible light with the aid of vanadium-based catalyst by selective aliphatic C-C single bond cleavage. Furthermore, the products could be used as fuels and feedstocks for chemical reactions.

Degradation of plastics by anodic oxidation link

Without the addition of chemicals, researchers reported that anodic oxidation can degrade the microplastics in water, turning them into harmless products – carbon dioxide and water. The reported degradation efficiency can be as high as 90%+ with a boron-doped diamond anode.

Wastewater link1 link2

A sustainable system that is used to purify wastewater was developed. Organic contaminants will be broken down into smaller, simpler molecules by a catalyst made of zinc oxide and cellulose.

Insights to removing micropollutants by studying nanoscale cooperative adsorption link

The interaction between ligands and nanoparticles was studied using a new imaging technique known as COMPEITS (COMPetition-Enabled Imaging Technique with Super-resolution). Understanding the factors that affect ligand adsorption opens up possibilities for designing catalytic adsorbent particles that can remove micropollutants, such as insecticides in the atmosphere.

Eradicating organic micropollutants in water with electrochemical systems link

An asymmetric, functionalized electrochemical cell was developed to remove organic micropollutants at parts-per-million concentrations. The cell demonstrates a high selectivity by suppressing water reduction and requires relatively low voltage and pressure to function. Regeneration of adsorbents was also plausible by reversing the polarity of electrodes.

Electrolytic removal of microplastics in wastewater directly at the source link

An efficient electrooxidation process was developed to degrade microplastics directly in artificially contaminated water. Hydroxyl radicals generated in electrooxidation attack the microplastics, yielding carbon dioxide and water. Future work would focus on the efficiency enhancement of the system in more complex water samples.

Turning banana peels into hydrogen link

Swiss Researchers have discovered an ultrafast biomass splitting process using flash light irradiation to turn dried biomass such as banana peel into valuable gases and solids, including hydrogen and biochar. This method can help reduce waste biomass and make use of the gases produced like hydrogen for industrial processes such as the Haber Process.

Reducing carbon dioxide concentration

Since the industrial revolution, the emissions of greenhouse gases, which absorb and emit infrared light to keep the Earth warm, have skyrocketed. It leads to extreme weather and the extinction of many species. To mitigate climate change, scientists are developing new technologies to reduce the concentration of carbon dioxide, which is the primary component of greenhouse gases, by providing more sustainable pathways for industrial processes, capturing carbon dioxide in the air, and converting carbon dioxide into simple organic molecules, etc.

Recent research directions

Direct capture of carbon dioxide in the air link1 link2

One of the possible ways to directly capture carbon dioxide in the air is to draw air with giant fans into potassium hydroxide solution and then mix it with calcium hydroxide solution to make limestones. These limestones will be collected and heated until a complete reaction takes place, leaving only calcium oxide and carbon dioxide. Eventually, carbon dioxide collected will be stored geologically underground.

Greener industrial production for ammonia link

Ammonia production is one of the most important industrial processes that feeds tens of millions of people. However, conventional ammonia production through the Haber-Bosch process is energy inefficient because it requires high temperatures and pressures for the reaction to take place. Researchers reported the incorporation of cadmium sulfide nanorod could efficiently transfer electrons to nitrogenase such that the conversion from molecular nitrogen to ammonia could be completed.

Making good use of carbon dioxide link

With the aid of a modified catalyst, researchers reported a more energy-efficient way to turn carbon dioxide into an industrially valuable molecule, ethylene. Compared to the previous attempt, this electrochemical system has a new coating added for better absorption of carbon dioxide on the catalytic surface.

Turning carbon dioxide into synthetic fuels link

Perovskite catalysts were fabricated to perform reserve water-gas shift reactions, aiming for transforming carbon dioxide into synthetic fuels and other valuable products. In principle, it can be implemented in industrial plants, which can provide a high concentration of carbon dioxide.

Low-temperature method to cut carbon emissions link

Researchers in the UK have devised a low-temperature method that could drastically cut the carbon emissions in manufacturing factories. The low-temperature process produces both calcium hydroxide and sodium carbonate which would absorb carbon dioxide and store them as useful minerals rather than being released to the environment.