Modification, adsorption, and geochemistry processes on altered minerals and amorphous phases on the nanometer scale: examples from copper mining refuse, Touro, Spain

Abstract

The sulfide oxidation and precipitation of Al-Fe-secondary minerals associated with abandoned acid mine drainage (AMD) from the abandoned copper mine waste pile at Touro, Spain, has been studied by sequential extraction (SE) combined with several techniques with the intent of understanding the role of these processes play in the natural attenuation of hazardous element contaminants in the AMD. In addition, the fragile nature of nanominerals and ultrafine particle (UFP) assemblages from contaminated sediment systems from the abandoned copper mine required novel techniques and experimental approaches. The investigation of the geochemistry of complex nanominerals and UFP assemblages was a prerequisite to accurately assess the environmental and human health risks of contaminants and cost-effective chemical and biogeological remediation strategies. Particular emphasis was placed on the study and characterization of the complex mixed nanominerals and UFP containing potentially toxic elements. Nanometer-sized phases in sediments were characterized using energy-dispersive X-ray spectrometer (EDS), field-emission scanning electron microscope (FE-SEM), and high-resolution transmission electron microscopy (HR-TEM) images. The identification of the geochemical and mineralogical composition of AMD in Touro, as well as the different formation mechanisms proposed, complement the existing literature on secondary mineral assemblages and provide new emphasis to increase the understanding of extreme environments. The results also demonstrated that variations in the geochemical fractionation of hazardous elements in AMD were more influenced by the secondary mineral proportion and by AMD pH.

Response of crops to fertilizer application in volcanic soils

“…The exchangeable K and Mg (Cmol c kg −1 ) values were converted to available K and Mg (mg kg −1 ) by multiplying the same by 390 and 120 (equivalent weight of the cations x 10), respectively. Similar analytical procedures were reported by several authors ( Dalmora et al, 2016a , 2016b , 2020a , 2020b ; Civeira et al, 2016 ). The soil samples were analyzed at the Soils Laboratory of Amhara Design and Supervision Works Enterprise.…”

Settling of Iron and Aluminum Particles in Acid Solutions for Acid Drainage Remediation

“…Higher settling velocities observed in iron suspensions emphasize the importance of iron flocs in the removal of contaminants in acid waters. This goes in addition to their previously reported importance from the chemical perspective [19,[52][53][54][55][56].…”

Indoor Nanoparticle Characterization in Construction Waste Recycling Companies over Time

“…It was also added for the analysis of NPs by HR-TEM. It should be noted that it was not necessary to prepare the collected samples to perform the AM (advanced microscopy) and XRD (X-ray powder diffraction) analyses [8,26,42], which in turn does not cause any change to the molecular structure of the analyzed particles [43][44][45][46][47][48]. The analysis of the collected material was carried out with the X-ray diffractometer NAPLOCK and X-ray Bruker (D8 DISCOVER) to identify the mineral and amorphous phases of the sampled chemical elements [49].…”