Remediation of contaminants from wastewater using algal nanoparticles via green chemistry approach: an organized review

Abstract

Bio-nanotechnology is one of the new and sound techniques that have various advantages over conventional methods of wastewater treatment. The utilization of nanomaterials like nanoparticles for wastewater treatment are emerging field of research. Both physical and chemical methods can be used for nanoparticle synthesis, but synthesis based on algae (biological method) has numerous advantages over others as it is environmentally friendly and sustainable. Top-down and bottom-up are the two approaches used for nanoparticle synthesis, generally, bio-reduction (bottom-up approach) is used to synthesize nanoparticles. Nanoparticles can be synthesized inside the cell of algae called intracellular synthesis and outside on the surface of the cell called extracellular synthesis. Temperature, pH, and reaction time are some of the factors that can influence the synthesis, size, and properties of nanoparticles. Characterization of nanoparticles is carried out with the help of the techniques like UV-Visible spectroscopy (UV-VIS), X-ray diffraction (XRD), Fourier transfer infrared spectroscopy (FTIR), etc. Algal nanoparticles are highly efficient in the remediation of contaminants like heavy metals and dyes from wastewater. In the present review, the utilization of algal nanoparticles for wastewater treatment containing contaminants like heavy metals, and dye, and various methods of synthesis of nanoparticles from algae are discussed. Moreover, the challenges and opportunities present in this field are also highlighted. As this field is in its initial stage, therefore, a lot of research gaps are present, which can only be filled by further new research.

Sustainable approach for adsorptive removal of cationic and anionic dyes by titanium oxide nanoparticles synthesized biogenically using algal extract of Spirulina

“…Dyes are used as colorants in numerous fields including the production of food, beauty articles, automobile industries, pharmaceutical, polymers, paint, tannery, and textile manufacturing. Shortage of fresh water can be resolved by sustainable harvesting of existing water resources and by more efficient technologies to treat wastewater [3][4][5][6].…”

“…These strategies not only remediate pollutants from wastewater but are also eco-friendly and thus possess no harm to the aquatic biodiversity. Nanoparticles because of having a high surface/ volume ratio, have more sites to adsorb pollutants this is the major supremacy of utilizing algal nano-adsorbents instead of biomass of algae for wastewater treatment [3][4][5][6][17][18][19][20][21].…”

Microalgae as a potential natural source for the green synthesis of nanoparticles

“…9,10 The exploration of new sources of microalgae-derived NPs can lead to the discovery of unique properties and innovative applications in nanotechnology, expanding the possibilities for use in various fields, e.g., NPs by microalgae have a variety of biomedical uses, including antibacterial, antifungal, antiviral, and anticancer, with great importance to society, 7 as well as their potential in environmental application for absorbing heavy metals, degrading dyes, and in pollutant bioremediation. 11,12 Their study can also contribute to food security by ensuring that feedstocks for synthesis do not compete with food resources 13 and do not adversely affect food production.…”