Micro circular economy conceptualized though the sustainable synthesis of a valuable opaline silica based microcidal, non-cytotoxic and free radical scavenging, composite from the dung of vechur cattle – A rare breed of bos taurus indicus

• Published in: Materials today : proceedings Vol. 46; pp. 2960 - 2968
• Main Authors: Mohan, Lekshmi, Archana, P., Varma, Muktha M., Kocherla, Murlidhar, Sreedhar, K.M., Sreekanth, K.M., Sivasubramanian, G.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-01-2021
• Subjects: Antimicrobial; Cow dung; Cytotoxicity; Opaline silica; Sustainability; Antimicrobial; Cytotoxicity; Cow dung; Sustainability; Opaline silica
• ISSN: 2214-7853; 2214-7853
• DOI: 10.1016/j.matpr.2020.12.422

Vechur breed is the smallest cattle of the world and the milk has natural abundant A2 form of β-casein proteins and hence milk and clarified butter become premier products for the farmer, fetching high returns. This indirectly accounts for the routine uniform composition of the dung, which can be utilized as a resource for extracting value-added products, thus initiating a circular economy at the microscale.
X-ray fluorescence (XRF) showed very high amounts of bio-metals like calcium, zinc and copper along with 21% silica enriched to 90% after burning. It was found that pure dung without any earthly contact is the best source, since earthly contact mixes up minerals like orthoclase which can cause phase change and structural alterations. Opaline silica supported Cu(II) was prepared by a simple sol–gel method. X-ray diffraction was generously employed to identify phase changes at each stage namely: acid treatment, combustion and metal incorporated precipitation, which showed the composite was a para-crystalline silica (opaline silica). Weight loss studies were carried out using thermogravimetry which collaborated well with XRF. Surface morphology showed irregular structure with particle dimensions of 700 nm. 87% of cell line survived in the MTT cytotoxic assay. The prepared composite showed anti-microbial activity against five pathogens and also exhibited excellent free radical scavenging activity against five radicals.
This study escorts the concept of circular economy, synthesizing (easy scale up) a versatile composite with potential microcidal environmental applications from raw cow dung, a biowaste.