Research article

EXTRACTION AND CHARACTERIZATION OF HUMIC SUBSTANCES (HUMIC ACID AND FULVIC ACID) FROM MUNICIPAL SOLID WASTE COMPOSTING

Researcher; Hussein N.Abd ¹& Assist. Prof. Hussein M. Flayeh ²

Online First: January 28, 2023


Aerobic composting is a typical biochemical process of stabilization and harmlessness of organic wastes during which organic matter degrades, and then aggregates, to produce humic substances HSs. HSs are a core product of—and a crucial indicator of—the maturation of compost that can be used in soil amendments. The formation of HSs is affected by the characteristics of the raw materials involved, the presence of compost additives, microbial activity, temperature, pH, the C/N ratio, moisture content, oxygen content and particle size, all ofwhich can interact with each other. The formation of HSs is therefore complex, moreover, it is difficult to identify definitive structures of humic acids (HA) and fulvic acids (FA), which are the two major components of (HSs). However,( HSs) represent the same functional groups and structural arrangements, which helps to predict their structures. Functional groups represented by phenol and carboxylic acid groups of (HA) and (FA) can provide various agronomic functions, such as plant growth enhancement, water and nutrient retention, and disease suppression capacity. Overall, (HSs) can act as a soil amendment, fertilizer,and plant growth regulator, these functions of (HSs) enhance the reuse potential of organic waste compost products; however, this requires scientific control of various composting parameters and appropriate application of final products. The purpose of this study is to follow the evolution of humic acids generated end of the composting of municipal and agricultural wastes, through the starting elements. analysis and spectroscopic methods (Fourier Transform Infra-Red) FTIR and Nuclear Magnetic Resonance: 13C-NMR), at the end of the composting process, the humic acids showed a greater abundance of aromatic structures while the levels of aliphatic molecules were strongly decreased, It can be seen that FA is mostly aliphatic/carbohydrate, while HA is mostly aliphatic/aromatic in terms of structural units, germination index (GI), and Humic matters (HMs), including humic substance (HS), humic acid (HA), and fulvic acid (FA), that the quality of the humic substances generated could be a useful indicator to evaluate the maturity of the final producd to assess its agronomic value, this confirms the stability of the final product after 35 days of composting.

Keywords

Humic acid (HA),Fulvic acid (FA), 13C nuclear magnetic resonance spectroscopy(13C NMR),Fourier transform-infrared spectroscopy(FTIR)