Water Purification by Carbon Quantum Dots

Abstract

Sustainable, sufficient and pure water is vital on earth at present. Of all processes used to purify water, nanotechnology plays an important role. Nanomaterials are available in all stages like membranes in filtration, adsorbents of pollutants, photocatalysts for degradation and for detection of pollutants in water purification. Carbon quantum dots (CQDs), an accidentally invented nanomaterial, like in many applications have supported in water purification in all stages. Hence, it is intended for a mini-review for the water purification techniques with carbon quantum dots (CQDs). The chapter consists of three parts. Many nanotechnological methods are employed in water purification. Among them, nanomembranes play a dominant role in detection, nanofiltration and degradation in water purification. Next, nanomaterials as adsorbents, sensors and photocatalytic activity for water remediation are being investigated largely. Hence, they are discussed in the first part. In the second part, the features of CQDs are considered for its versatile applications. The easy and low-cost preparation of CDQs from easily available materials are investigated from the research published articles. In the third part, an attempt is made to collectively analyze the CQDs contributions as membranes in water purification, to detect the presence of organic, inorganic and dye contamination from water is reviewed. Further, the removal of the harmful and or toxic elements from polluted and impure water is discussed from various research groups.

Carbon Quantum Dots: Properties, Preparation, and Applications

“…These methods effectively intercept large impurities while allowing carbon quantum dots and small molecules to pass through the membrane. After removing the large impurities, it is necessary to use dialysis and other methods to remove small molecule impurities from the carbon quantum dot material [103].…”

Applications of Quantum Dots in the Food Industry

“…These membranes also are utilized in reverse osmosis because of enhanced water permeability, high permeation flux, and antifouling capability. By incorporating CQDs on the membrane surfaces, all processes like desalination performance, porosity, permeability, hydrophilicity, selectivity are increased [79].…”

“…CQDs transfer electrons at different positions and can reduce the recombination of light-generated charges. All the mentioned properties have made them an appropriate candidate for water purification and removal of organic and inorganic pollutants from water [79].…”

“…N-CQDs were with success incorporated into this treatment. Another adsorbent, polyethyleneimine-functionalized CQDs onto the magnetic materials (MnFe 2 O 4 ) to provide a nanocomposite (PECQDs/ MnFe 2 O 4 ), is applied for the removal of uranium [79].…”