Comparative effectiveness of activated dolomite phosphate rock and biochar for immobilizing cadmium and lead in soils

The Synergistic Effect of Biochar-Combined Activated Phosphate Rock Treatments in Typical Vegetables in Tropical Sandy Soil: Results from Nutrition Supply and the Immobilization of Toxic Metals

“…It could increase the release of P, Ca, and Mg in phosphate rocks due to the complexation and chelation of these elements into bioavailable forms. Our previous study proved that both the humic acid activated phosphate rock and the biochar had great potential to remedy the toxic levels of Cd and Pb in contaminated sandy soils, but their agronomic and nutrition supply effects on the plants still need to be explored further [ 28 ]. Thus, the effects of biochar, activated phosphate rock, and a combination of the two on plant growth and the uptake of nutrition by plants were investigated in this work.…”

“…To fabricate the activated phosphate rock, phosphate rock samples were ground to less than 100 mesh and then activated by humic acid as per the previous study [ 28 ]. Briefly, the phosphate rock samples were thoroughly mixed with humic acid (5%), and then deionized water (15% moisture) was added.…”

“…Our previous study showed that the application of humic acid-activated dolomite phosphate rock and biochar were effective amendments for immobilizing heavy metals in contaminated sandy soils, and the humic acid-activated dolomite phosphate rock reduced the amount of extractable Cd 2+ and Pb 2+ by 87.2 and 76.0% in Alfisol and by 91.3 and 76.3% in Spodosol soil, respectively, compared to the control [ 28 ]. Biochar’s nutrient supply and adsorption capacities are due to its large surface area, highly porous structure and strong ion exchange capacity, and because of this, the combination of activated phosphate rock and biochar may exhibit an excellent effect not only for toxic metal passivation but also for the ability of vegetables to uptake nutrients.…”

In situ synthesis of zeolites by geopolymerization with NaOH/KOH mixed solution and their potential application for Cd(II) immobilization in paddy soil

“…zeolite, bentonite and sepiolite) and similar to that of biochar. Some previous studies (Shaha et al, 2012;Hamid et al, 2020;Liu et al, 2021) indicated that an increase of soil pH with alkaline materials may be associated with improved Cd precipitation and adsorption. In this study, the pH value increased with the addition of greater amounts of geopolymer due to the alkaline nature of the material added (Fig.…”

Cadmium distribution in soils, soil litter and cacao beans: a case study from Colombia

“…According to previous studies (Trakal et al 2011;Scaccabarozzi et al 2020;Ondrasek et al 2021;Rumney et al 2021), liming using dolomitic limestone, restricted metal leaching from the soil substrate and, at the same time, in willow, alleviated plant stress imposed by toxic elements resulting in better plant growth. Moreover, a very recent paper (Liu et al 2021) shows the benefits of dolomite phosphate rock (DPR), humic acid-activated dolomite phosphate rock (ADPR) and biochar (BC) in immobilizing Cd in subtropical soils. However, regarding the application in cocoa crops during the past years, although the application of liming material such as dolomite it has been extensively studied as an option to stabilize Cd in the soil, neutralize acidic soil and enhance metal stabilization in soil by reducing the extractable Cd concentration (Hamid et al 2018;Ramtahal et al 2019;Argüello et al 2020), it has been shown that this technique needs to be reconsidered due to its efficiency in terms of time and cost for cacao in field.…”