Application of humic acid and hydroxyapatite in Cd-contaminated alkaline maize cropland: A field trial.

Soil quality is critical to the quality and safety of agricultural products, and remediation of heavy metal contaminated soils is an urgent task to be implemented. This study applied hydroxyapatite (HAP) and humic acid (HA) as remediation materials to Cd-contaminated alkaline cropland. Data on soil pH, electrical conductivity (EC), cation exchange capacity (CEC), soil organic matter (SOM), diethylenetriamine pentaacetic acid (DTPA) extraction, and improved BCR sequential extraction were obtained for different periods.

Determination of interactions of ferrihydrite-humic acid-Pb (II) system.

Ferrihydrite often precipitates with humic acid in natural ways, affecting the fate of lead ions, the stabilization of humic acid, and the aging process of ferrihydrite. A series of 2-line ferrihydrite-humic (Fh-HA) acid with varying C loadings has been prepared, the morphology and surface properties of Fh-HA organo-minerals have been characterized, and the adsorption property of Pb ions onto Fh-HA has been studied. The results indicated that a strong interference of HA to ferrihydrite 2-line Fh dominated mineral phase in all samples, but with increasing C/Fe molar ratios, the crystallinity gradually weakened, particles became smaller, and SSA decreased significantly.