High decrease in soil metal bioavailability by metal immobilization with halloysite clay

Abstract

Increasing pollution by heavy metals calls for advanced methods to immobilize or extract soil metals, thus avoiding their contact with water, air and living organisms. In particular there is a need for cheap binding materials that extract metals. Here we tested the use of the halloysite clay, functionalized with silanes and non-functionalized, on metal extraction from soils. The clay was functionalized with 3-mercaptopropyl-trimethoxysilane and 3-[2-(2-aminoethylamino)ethylamino]propyltrimethoxysilane. Contaminated soils were sampled at the Głogów Copper Smelter and Refinery. Soils were sequentially extracted using the Tessier method. Metals were quantified by atomic absorption spectroscopy. Our results show that the addition of halloysite increases the metal content of the plant unavailable fraction that is the fifth fraction of the Tessier method, thus decreasing metal availability. Indeed metal contents of the fifth fraction versus total content increased from 67.64 to 157.79 mg/kg for copper, from 28.10 to 76.14 mg/kg for lead, from 41.60 to 95.78 mg/kg for zinc, from 0.77 to 1.79 mg/kg for cadmium and from 3.96 to 8.90 mg/kg for arsenic.

Preparation, Characterization of Granulated Sulfur Fertilizers and Their Effects on a Sandy Soils

“…Thus, these ions are also considered as bioavailable [83]. Elemental sulfur is not directly available for plants, until it is oxidized to sulfate ions SO 4 2− [20]. There are many factors that influence the oxidation process.…”

“…Elemental sulfur (Figure 1a,d) is produced predominantly by recovery from the oil and gas industry. The low price of this material has recently stimulated its wider use [20]. There are various methods of biogas desulfurization.…”

Diffusive gradient in thin films with open and restricted gels for predicting mercury uptake by plants

“…The texture of the agricultural soil had a higher sorption capacity in comparison with the control soil because of the higher clay content in soil and, depending on the organic acids, organic matter could reduce or increase Hg bioavailability by forming insoluble or soluble complexes (Hasegawa et al, 2016). In this sense, adsorbents such as clay minerals and modified clays are effective for the removal of metal ions from wastewater (Gu et al, 2018), and from soils (Kurczewska et al, 2015).…”

Evidence for a correlation between total lead concentrations in soils and the presence of geological faults

“…It has been reported that more than 43% of the lead present in soil is found in the organic soil fraction, with the remainder bound to other components of the soil system, such as oxides and hydroxides of iron and aluminum, as well as carbonates and phosphates (Shaheen et al 2013;Xian 1989). An excess of negative charges on the surfaces of the soil particles results in the attraction of cations from the soil liquid phase and other particles (Kurczewska et al 2015). This adsorption process, involving weak and reversible ionic bonding, is known as the cation exchange capacity (CEC).…”