Synthesis of calcium carbonate nanoparticles from mollusc shell waste and its efficacy towards plant growth and development

Sustainable waste management and adequate food supply for a rapidly increasing population are the major goals in the 21st century. In the present study, calcium carbonate nanoparticles (CCNPs) were synthesized from mollusc shell waste and explored its efficacy towards the growth and development of Cicer arietinum L. seedlings. Initially, seeds were allowed to germinate and grow with different concentrations (0, 10, 20, and 30 mg/L) of synthesized CCNPs, and the growth attributes of seedlings were analyzed. The characterization of synthesized nanoparticles revealed that the synthesized nanoparticles were spherical with a diameter ranging from 60 to 70 nm. The results of the growth experiment showed that CCNPs enhanced seed germination, seedling growth, photosynthetic pigments, and primary metabolite content. Additionally, a low level of oxidative stress was recorded under all treatments of CCNPs, and the highest decrease in MDA and O₂•^- contents of about 12 % and 23 % were recorded under 30 mg/L of CCNPs compared to the control, respectively. The antioxidant system was improved under CCNPs treatments and the highest increase of about 22 % and 37 % in CAT and SOD activity were recorded at 30 mg/L of CCNPs compared to the control, respectively. The anatomical study suggested that the vascular bundle developed much better in nano-treated seedlings compared to the control and CCNPs have no adverse impact on seedling development. Therefore, the present research demonstrated a sustainable approach to the management of solid waste through the formulation of CCNPs, which could be a potential nanofertilizer in the agricultural sector.