Development of green nutrient delivery substrates for hydroponics culture

• Main Author: Tan, Hui Lin
• Other Authors: Ng Kee Woei
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2021
• Subjects: Engineering::Materials
• Online Access: https://hdl.handle.net/10356/147812
• Institution: Nanyang Technological University

Human hair is an abundant and renewable resource that is largely discarded as waste materials. Due to its composition, human hair has immense potential as an agricultural fertiliser. A major component of human hair is keratin, which has essential nutrients required for plant growth such as nitrogen. Hence, this study aims to utilise keratin extracted from human hair to fabricate a hydroponics substrate, in the form of a composite sponge. The composite sponge is composed of keratin, cellulose fibres, and may include copper-carbon dots. The cellulose fibres are added as reinforcement, while the copper-carbon dots serve as reinforcement and additional nutrient source. In this study, the physicochemical properties and aqueous environment stability of the keratin-based composite sponges consisting of cellulose microfibres (CMF) and cellulose nanofibres (CNF) were compared. Fourier Transform Infrared Spectroscopy (FTIR) revealed that the chemical structures of keratin and cellulose remained intact within the sponge. Scanning Electron Microscopy (SEM) showed that cellulose and copper-carbon dots reinforced the porous structure of keratin. The pore structures of the keratin-based sponge containing CMF or CNF were similar, and there were no significant differences for their porosity and water uptake tests. Interestingly, the sponge that consists of CMF showed better stiffness during the compression test than that with CNF. There were also different rates of protein release at several time points for both sponges. Pak Choy (Brassica rapa subsp. chinensis) and Alfalfa (Medicago sativa) plant tests were conducted with the composite sponges to determine their effectiveness in plant growth enhancement against the commercial substrate Oasis cube (control) and to compare the effectiveness of sponges made from CMF and CNF. Our findings demonstrated the ability of the composite sponges in enhancing plant growth, and their potential as hydroponics substrate that can also function as agricultural fertiliser.