Cd2+ Ions Removal from Aqueous Solutions Using Alginite

Alginate has been evaluated as an efficient pollution control material. In this paper, alginate from maar Pinciná (SR) for removal of Cd2+ ions from aqueous solution was studied. The potential sorbent was characterized by X-Ray Fluorescence Analysis (RFA) analysis, Fourier Transform Infrared Spectral Analysis (FT-IR) and Specific Surface Area (SSA) was also determined. The sorption process was optimized from the point of initial cadmium concentration effect and effect of pH value. The Freundlich and Langmuir models were used to interpret the sorption behaviour of Cd2+ ions, and the results showed that experimental data were well fitted by the Langmuir equation. Alginate maximal sorption capacity (QMAX) for Cd2+ ions calculated from Langmuir isotherm was 34 mg/g. Sorption process was significantly affected by initial pH value in the range from 4.0-7.0. Alginate is a comparable sorbent with other materials for toxic metals removal

Preparation and characterization of novel magnesium composite/walnut shells-derived biochar for as and p sorption from aqueous solutions

Unidad de excelencia María de Maeztu CEX2019-000940-MElevated or unnatural levels of arsenic (As) and phosphorus (P) concentrations in soils and waterbodies from anthropogenic sources can present significant hazards for both natural ecosystems and human food production. Effective, environmentally friendly, and inexpensive materials, such as biochar, are needed to reduce mobility and bioavailability of As and P. While biochar features several physicochemical properties that make it an ideal contaminant sorbent, certain modifications such as mineral-impregnation can improve sorption efficiencies for targeted compounds. Here, we conducted sorption experiments to investigate and quantify the potential utility of magnesium (Mg) for improving biochar sorption efficiency of P and As. We synthesized a Mg-modified walnut shells-derived biochar and characterized its ability to remove As and P from aqueous solutions, thereby mitigating losses of valuable P when needed while, at the same time, immobilizing hazardous As in ecosystems. SEM-EDX, FTIR and elemental analysis showed morphological and functional changes of biochar and the formation of new Mg-based composites (MgO, MgOHCl) responsible for improved sorption potential capacity by 10 times for As and 20 times for P. Sorption efficiency was attributed to improved AEC, higher SSA, chemical forms of sorbates and new sorption site formations. Synthetized Mg-composite/walnut shell-derived biochar also removed >90% of P from real samples of wastewater, indicating its potential suitability for contaminated waterbody remediation

Biochar from Wood Chips and Corn Cobs for Adsorption of Thioflavin T and Erythrosine B

Biochars from wood chips (WC) and corn cobs (CC) were prepared by slow pyrolysis and used for sorption separation of erythrosine B (EB) and thioflavin T (TT) in batch experiments. Biochar-based adsorbents were extensively characterized using FTIR, XRD, SEM-EDX, and XPS techniques. The kinetics studies revealed that adsorption on external surfaces was the rate-limiting step for the removal of TT on both WC and CC biochar, while intraparticle diffusion was the rate-limiting step for the adsorption of EB. Maximal experimental adsorption capacities Q(maxexp) of TT reached 182 +/- 5 (WC) and 45 +/- 2 mg g(-1) (CC), and EB 12.7 +/- 0.9 (WC) and 1.5 +/- 0.4 mg g(-1) (CC), respectively, thereby indicating a higher affinity of biochars for TT. The adsorption mechanism was found to be associated with pi-pi interaction, hydrogen bonding, and pore filling. Application of the innovative dynamic approach based on fast-field-cycling NMR relaxometry indicates that variations in the retention of water-soluble dyes could be explained by distinct water dynamics in the porous structures of WC and CC. The obtained results suggest that studied biochars will be more effective in adsorbing of cationic than anionic dyes from contaminated effluents

Biochar from Wood Chips and Corn Cobs for Adsorption of Thioflavin T and Erythrosine B

Biochars from wood chips (WC) and corn cobs (CC) were prepared by slow pyrolysis and used for sorption separation of erythrosine B (EB) and thioflavin T (TT) in batch experiments. Biochar-based adsorbents were extensively characterized using FTIR, XRD, SEM-EDX, and XPS techniques. The kinetics studies revealed that adsorption on external surfaces was the rate-limiting step for the removal of TT on both WC and CC biochar, while intraparticle diffusion was the rate-limiting step for the adsorption of EB. Maximal experimental adsorption capacities Qmaxexp of TT reached 182 ± 5 (WC) and 45 ± 2 mg g−1 (CC), and EB 12.7 ± 0.9 (WC) and 1.5 ± 0.4 mg g−1 (CC), respectively, thereby indicating a higher affinity of biochars for TT. The adsorption mechanism was found to be associated with π-π interaction, hydrogen bonding, and pore filling. Application of the innovative dynamic approach based on fast-field-cycling NMR relaxometry indicates that variations in the retention of water-soluble dyes could be explained by distinct water dynamics in the porous structures of WC and CC. The obtained results suggest that studied biochars will be more effective in adsorbing of cationic than anionic dyes from contaminated effluents

Removal of Synthetic Dyes by Dried Biomass of Freshwater Moss Vesicularia Dubyana: A Batch Biosorption Study

In this work the biosorption of cationic dyes thioflavin T (TT) and methylene blue (MB) from single and binary solutions on dried biomass of freshwater moss Vesicularia dubyana as a function of contact time, pH, and biomass or sorbate concentration has been investigated. The prediction of maximum sorption capacities using adsorption isotherm models were also realized. Biosorption of TT and MB is a rapid process strongly affected by solution pH. Maximum sorption capacities Qmax calculated from Langmuir isotherm were 119 ± 11 mg/g for TT and 229 ± 9 mg/g for MB. In binary mixture, the presence of MB caused significant decrease of TT sorption, advocating the competitive sorption between TT and MB. Results revealed that V. dubyana biomass exhibited significantly higher affinity to thiazine dye MB in comparison with benzothiazole dye TT from both single and binary solutions. Based on the obtained results, the competitive effects in binary system can substantially influence the sorption process and should be thoroughly evaluated before application of selected adsorbents for removal of basic dyes from colored effluents

Comparison Of Cd2+ Biosorption And Bioaccumulation By Bacteria – A Radiometric Study

In this work, bioaccumulation and biosorption characteristics of Cd2+ ions by both dead and living non-growing biomass of gram-positive bacteria Kocuria palustris and Micrococcus luteus isolated from spent nuclear fuel pools were compared. The radioindicator method with radionuclide 109Cd was used to obtain precise and reliable data characterizing Cd compartmentalization in bacterial cells. The following cellular distribution of Cd in living non-growing biomass after 4 h incubation in solutions containing different concentration of Cd2+ ions (100, 250, 500, 750 and 1000 µmol/L) spiked with 109CdCl2 under aeration at 30 °C were obtained: in M. luteus almost 85 % of Cd was localized on the cell surface and 15 % in cytoplasm. Similarly, in K. palustris 83 % of Cd was localized on the cell surface and 17 % in cytoplasm. The data were obtained by gamma spectrometry of extracts and solids after sequential extraction of biomass with 5 mM Ca(NO3)2 and 20 mM EDTA. Biosorption of Cd by non-living bacterial biomass is a rapid process strongly affected by solution pH and as was confirmed by FTIR analysis beside carboxylate ions also other functional groups such as amino and phosphate contribute to Cd binding by bacterial cell surfaces. Maximum sorption capacities Qmax (μmol/g) calculated from the Langmuir isotherm were 444 ± 15 μmol/g for M. luteus and 381 ± 1 μmol/g for K. palustris

Removal of Synthetic Dyes by Dried Biomass of Freshwater Moss Vesicularia Dubyana: A Batch Biosorption Study

In this work the biosorption of cationic dyes thioflavin T (TT) and methylene blue (MB) from single and binary solutions on dried biomass of freshwater moss Vesicularia dubyana as a function of contact time, pH, and biomass or sorbate concentration has been investigated. The prediction of maximum sorption capacities using adsorption isotherm models were also realized. Biosorption of TT and MB is a rapid process strongly affected by solution pH. Maximum sorption capacities Qmax calculated from Langmuir isotherm were 119 ± 11 mg/g for TT and 229 ± 9 mg/g for MB. In binary mixture, the presence of MB caused significant decrease of TT sorption, advocating the competitive sorption between TT and MB. Results revealed that V. dubyana biomass exhibited significantly higher affinity to thiazine dye MB in comparison with benzothiazole dye TT from both single and binary solutions. Based on the obtained results, the competitive effects in binary system can substantially influence the sorption process and should be thoroughly evaluated before application of selected adsorbents for removal of basic dyes from colored effluents

Chemometric Characterization of Synthetic Dye Sorption onto Slovakian River Sediments: A Laboratory Batch Experiment

The aim of the work was to characterize the sorption of cationic dyes thioflavine T (ThT) and methylene blue (MB) onto selected Slovakian river sediments using chemometric approaches including principal component analysis (PCA) and cluster analysis (CA). Also, the potential of mentioned multivariate analyses for comparison of studied objects (river sediments or river and model waters) as well as in finding relationships between the variables describing the physico-chemical characteristics of studied matrices or waters and sorption/desorption characteristics of matrices for dyes binding under laboratory conditions was evaluated. Parameters describing the physico-chemical characteristics of sediments include: pH, pHzpc, or cation-exchange capacity; and in the case of waters: pH, conductivity, water hardness, content of dissolved solids or presence of organic compounds. From the comparison of dye sorption onto sediments, it was found that sorption of thiazine dye MB was minimally 1.5-times higher than sorption of benzothiazole dye ThT. Sorption capacities Qs reached the maximum values in the case of sediments originated from Dudvah River (MB-Qs = 8.70 ± 0.42 mg g−1; ThT-Qs = 5.03 ± 0.28 mg g−1; ±SD). Obtained results showed that applied methods of multivariate analyses represent a suitable tool for evaluation of sorption/desorption processes of organic xenobiotics binding in sediments