Extraction of Humic Acids from Different Origins: A Review

Abstract

The synthesis of molecules such as humic acids is a good strategy for the remediation of eroded soils. Since the synthesis and extraction of these carbon molecules do not represent a process of energy liberation of the carbon, it is also a low-cost process. Bad practices in soils, such as the indiscriminate use of pesticides and pesticides, cause damage to the soil that can be difficult to reverse, depending on the type of exposure and resilience they have. For example, the Atlantic coast is the most affected by salinization, according to Ideam a phenomenon related to incorrect agricultural activities, devastating tourism, and the impact of the dry climate. Soil erosion is an effect that has a negative influence on activities such as agriculture since the erosion of the soils prevents or causes the agricultural activity to be low or almost nil. Humic acids are molecules that can retain cations in their macroporous structure. Therefore, it is important to study what is the affinity that these macromolecules have with the cations of Zn, Ca, K, Mg and therefore, to know with which of them the affinity is greater depending on the type of carbon studied. The objective of this monographic study is to review the conceptual part of humic acids, their different forms of extraction, and their applications reported by different authors working in this field.

Preparation of Humic Acid from Weathered Coal by Mechanical Energy Activation and Its Properties

“…Moreover, China has a large number of coal mines, so the amount of weathered coal produced each year is extremely large, and a large amount of weathered coal is in urgent need of development and utilization. Typically, the total HA content of weathered coal ranges from 30 to 70%, with higher levels reaching more than 70% [9]. Weathered coal with high total HA content can be utilized directly, e.g., for soil improvement, wastewater treatment, radioactive waste disposal [10], etc.…”

Humic Acids as a New Type of Methane Hydrate Formation Promoter and a Possible Mechanism for the Hydrate Growth Enhancement

“…Humic acids (HAs) are widespread natural compounds (components of soil, brown coal, etc. ), exhibiting the properties of surfactants. , In addition to brown coal, peat, leonardite, compost, soils, lignins, and some others can act as sources of HAs . They have a complex composition.…”

“…29,30 In addition to brown coal, peat, leonardite, compost, soils, lignins, and some others can act as sources of HAs. 31 They have a complex composition. Carboxylic, keto, and hydroxyl groups are dominant among the functional groups of these compounds.…”