Modified Activated Carbon for Copper Ion Removal from Aqueous Solution

Because of increasing environmental awareness, it is becoming more important to remove harmful elements from water solutions. This study used activated carbon (AC) derived from waste wood-based panels as the base material, oxidized with nitric acid (OAC), and grafted with iminodiacetic acid (IDA-OAC) to improve the adsorption capacity and affinity for metals. The characterization of AC, OAC, and IDA-OAC was conducted via FTIR, SEM, N2 adsorption and desorption analysis, elemental analysis, Boehm titration, and point of zero charge (PZC). The instrument studies proved the modified increasing of the functional groups of the adsorbents. Moreover, batch and column experiments were conducted to evaluate the ability of the three adsorbents to remove copper ions from aqueous solution. In batch sorption, IDA-OAC had the highest adsorption capacity (84.51 mg/g) compared to OAC (54.74 mg/g) and AC (24.86 mg/g) at pH 5. The breakthrough point (Ct/Ci = 0.05) of copper ions for IDA-OAC occurred much later than AC in the column experiment (AC = 19 BV, IDA-OAC = 52 BV). The Langmuir isotherm and pseudo-second-model kinetics modeling could better fit with the data obtained from the batch sorption of AC, OAC, and IDA-OAC. The significant capacity and reusability of IDA-OAC displayed high applicability for water treatment.

Surface Charge governs the adsorption behaviour of glyphosate in Australian Oxisol Soil System

Glyphosate adsorption pattern is important for determining its environmental fate. Oxisol soil systems adsorb maximum glyphosate in the presence of biochar, however, the mechanism was not known. This article provides information concerning the role of surface charge in the case of Oxisol soil systems. Batch sorption experiments were conducted at the University of Sydney, Australia. Potentiometric titrations were done to calculate the surface charge in the case of Oxisol soil systems. Maximum adsorption of glyphosate in the Oxisol soil systems in the presence of char was due to an increase in net positive surface charge. This finding is of great importance to understanding the mechanism of herbicide soil interactions.

Surface Charge governs the adsorption behaviour of glyphosate in Australian Oxisol Soil System

Glyphosate adsorption pattern is important for determining its environmental fate. Oxisol soil systems adsorb maximum glyphosate in the presence of biochar, however, the mechanism was not known. This article provides information concerning the role of surface charge in the case of Oxisol soil systems. Batch sorption experiments were conducted at the University of Sydney, Australia. Potentiometric titrations were done to calculate the surface charge in the case of Oxisol soil systems. Maximum adsorption of glyphosate in the Oxisol soil systems in the presence of char was due to an increase in net positive surface charge. This finding is of great importance to understanding the mechanism of herbicide soil interactions.

Surface Charge governs the adsorption behaviour of glyphosate in Australian Oxisol Soil System

Glyphosate adsorption pattern is important for determining its environmental fate. Oxisol soil systems adsorb maximum glyphosate in the presence of biochar, however, the mechanism was not known. This article provides information concerning the role of surface charge in the case of Oxisol soil systems. Batch sorption experiments were conducted at the University of Sydney, Australia. Potentiometric titrations were done to calculate the surface charge in the case of Oxisol soil systems. Maximum adsorption of glyphosate in the Oxisol soil systems in the presence of char was due to an increase in net positive surface charge. This finding is of great importance to understanding the mechanism of herbicide soil interactions.

Comparison of Sr Transport in Compacted Homoionous Na and Ca Bentonite Using a Planar Source Method Evaluated at Ideal and Non-Ideal Boundary Condition

With the aim to determine the influence of dominant interlayer cation on the sorption and diffusion properties of bentonite, diffusion experiments with Sr on the compacted homoionous Ca- and Na-forms of Czech natural Mg/Ca bentonite using the planar source method were performed. The bentonite was compacted to 1400 kg·m−3, and diffusion experiments lasted 1, 3 or 5 days. Two methods of apparent diffusion coefficient Da determination based on the analytical solution of diffusion equation for ideal boundary conditions in a linear form were compared and applied. The determined Da value for Ca-bentonite was 1.36 times higher than that for Na-bentonite sample. Values of Kd were determined in independent batch sorption experiments and were extrapolated for the conditions of compacted bentonite. In spite of this treatment, the use of Kd values determined by batch sorption experiments on a loose material for the determination of effective diffusion coefficient De values from planar source diffusion experiments proved to be inconsistent with the standard Fickian description of diffusion taking into account only the pore diffusion in compacted bentonite. Discrepancies between Kd and De values were measured in independent experiments, and those that resulted from the evaluation of planar source diffusion experiments could be well explained by the phenomenon of surface diffusion. The obtained values of surface diffusion coefficients Ds were similar for both studied systems, and the predicted value of total effective diffusion coefficient De(tot) describing Sr transport in the Na-bentonite was four times higher than in the Ca-bentonite.

Microbial Community Composition Correlates with Metal Sorption in an Ombrotrophic Boreal Bog: Implications for Radionuclide Retention

Microbial communities throughout the 6.5 m depth profile of a boreal ombrotrophic bog were characterized using amplicon sequencing of archaeal, fungal, and bacterial marker genes. Microbial populations and their relationship to oxic and anoxic batch sorption of radionuclides (using radioactive tracers of I, Se, Cs, Ni, and Ag) and the prevailing metal concentrations in the natural bog was investigated. The majority of the detected archaea belonged to the Crenarchaeota, Halobacterota, and Thermoplasmatota, whereas the fungal communities consisted of Ascomycota, Basidiomycota, and unclassified fungi. The bacterial communities consisted mostly of Acidobacteriota, Proteobacteria, and Chloroflexi. The occurrence of several microbial genera were found to statistically significantly correlate with metal concentrations as well as with Se, Cs, I, and Ag batch sorption data. We suggest that the metal concentrations of peat, gyttja, and clay layers affect the composition of the microbial populations in these nutrient-low conditions and that particularly parts of the bacterial and archaeal communities tolerate high concentrations of potentially toxic metals and may concurrently contribute to the total retention of metals and radionuclides in this ombrotrophic environment. In addition, the varying metal concentrations together with chemical, mineralogical, and physical factors may contribute to the shape of the total archaeal and bacterial populations and most probably shifts the populations for more metal resistant genera.