Assessment of heavy metal pollution from anthropogenic activities and remediation strategies: A review.

Biochar modification to enhance sorption of inorganics from water

Recently, biochar has received significant attention, especially for the removal of potentially toxic elements (PTEs) from water and wastewater. No review has been focused on the potential use of wood-based biochar (WB) for the removal of PTEs in water and wastewater. Here, we have critically reviewed the (i) preparation and characterisation of WB; (ii) removal efficiency of WB for PTEs in water with respect to its physicochemical characteristics, biochar/water ratio, pH, and sorption system; (iii) removal mechanisms of PTEs by WB; (iv) fate of the sorbed PTEs onto WB; and (v) recovery of the sorbed PTEs from the resultant sludge of WB. We also discussed the removal of PTEs by engineered/designer WB as compared to pristine WB. This review demonstrates the overarching scientific opportunities for a comprehensive understanding of using WB as an emerging biosorbent and a promising low-cost and effective material for the remediation of PTEs contaminated water.

Wood-based biochar for the removal of potentially toxic elements in water and wastewater: a critical review

The solid-liquid interface reaction between phosphate rock (PR) and metals (Pb, Cu, and Zn) was studied. Phosphate rock has the highest affinity for Pb, followed by Cu and Zn, with sorption capacities of 138, 114, and 83.2 mmol/kg PR, respectively. In the Pb-Cu-Zn ternary system, competitive metal sorption occurred with sorption capacity reduction of 15.2%, 48.3%, and 75.6% for Pb, Cu, and Zn, respectively compared to the mono-metal systems. A fractional factorial design showed the interfering effect in the order of Pb>Cu>Zn. Desorption of Cu and Zn was sensitive to pH change, increasing with pH decline, whereas Pb desorption was decreased with a strongly acidic TCLP extracting solution (pH = 2.93). The greatest stability of Pb retention by PR can be attributed to the formation of insoluble fluoropyromorphite [Pb(10)(PO(4))(6)F(2)], which was primarily responsible for Pb immobilization (up to 78.3%), with less contribution from the surface adsorption or complexation (21.7%), compared to 74.5% for Cu and 95.7% for Zn. Solution pH reduction during metal retention and flow calorimetry analysis both supported the hypothesis of retention of Pb, Cu, and Zn by surface adsorption or complexation. Flow calorimetry indicated that Pb and Cu adsorption onto PR was exothermic, while Zn sorption was endothermic. Our research demonstrated that PR can effectively remove Pb from solutions, even in the presence of other heavy metals (e.g. Cu, Zn).

https://digitalcommons.calpoly.edu/cgi/viewcontent.cgi?article=1014&context=ersc_fac

Understanding the Mechanisms of Lead, Copper, and Zinc Retention by Phosphate Rock

Microporous materials such as zeolites, metal organic frameworks, activated carbons and aluminum phosphates are suitable for catalysis and separation applications. These high surface area materials are invariably produced in particulate forms and need to be transformed into hierarchically porous structures for high performance adsorbents or catalysts. Structuring of porous powders enables an optimized structure with high mass transfer, low pressure drop, good heat management, and high mechanical and chemical stability. The requirements and important properties of hierarchically porous structures are reviewed with a focus on applications in gas separation and catalysis. Versatile powder processing routes to process porous powders into hierarchically porous structures like extrusion, coatings of scaffolds and honeycombs, colloidal processing and direct casting, and sacrificial approaches are presented and discussed. The use and limitations of the use of inorganic binders for increasing the mechanical strength is reviewed, and the most important binder systems, e.g. clays and silica, are described in detail. Recent advances to produce binder-free and complex shaped hierarchically porous monoliths are described and their performance is compared with traditional binder-containing structured adsorbents. Needs related to better thermal management and improved kinetics and volume efficiency are discussed and an outlook on future research is also given.

https://cyberleninka.org/article/n/1017336.pdf

Structuring adsorbents and catalysts by processing of porous powders

Radioisotope of nickel 63Ni is an important product of the neutron activation in engineering materials of nuclear power plants. Adsorption of nickel on Slovak rhyolitic bentonites Jelsový potok, Kopernica and Lastove was studied using batch method. Radionuclide 63Ni was used as a tracer. In this paper, we focused on effects of contact time, pH, competitive cations and equilibrium study. This study showed that Slovak rhyolitic bentonites are a promising candidate for removal of radionickel from aqueous solutions.

Adsorption of nickel on rhyolitic Slovak bentonites

Adsorption of nickel on Slovak andesitic ben- tonite Lieskovec was studied using batch method. As a tracer was used radionuclide 63 Ni. In this paper, we focused on effects of contact time, pH, competitive cations and equilibrium study using Langmuir model. Studied material has proved good adsorption ability and it can be used in the field of waste management for removal of radionickel from aqueous solutions.

Adsorption of nickel on andesitic bentonite Lieskovec

Pyrogenic materials produced from various input materials and with valuable characteristics such as high porosity, extensive surface area, and mineral composition represent alternative to traditional carbon-based materials in area of contaminant immobilization, aqueous solutions purification, and soil remediation. Intensification of industry and technological processes brings increased use of lanthanides and thus potential risk of lanthanide penetration into soil and aquatic systems. This study examined the roles of three different pyrogenic materials: microcrystalline cellulose-derived pyrogenic materials (MCPM), organic cotton-derived pyrogenic material (OCPM), and sewage sludge-derived pyrogenic material (SSPM) produced in the process of slow pyrolysis at 430 °C in N2 atmosphere as potential Eu immobilization and sorption materials. Produced materials were characterized by determination of wide range physicochemical properties via elemental analysis, SEM, FT-IR, and sorption potential for Eu in batch sorption experiments. The obtained data confirmed that sorption separation of Eu by OCPM, MCPM, and SSPM from aqueous solution is relatively rapid process with reached equilibrium at 24 h. Batch equilibrium experiments revealed maximum sorption capacities 0.602 mg g−1 for MCPM, 1.761 mg g−1 for OCPM, and 2.586 mg g−1 for SSPM. The presence of co-ions such as Al in system reduced sorption potential about more than 50% for all three studied materials. Column leaching test with artificially contaminated soil and 5% (w/w) amendments of pyrogenic materials showed significant retention ability of MCPM, OCPM, and SSPM for mobile Eu forms compared to control soil. Pyrolysis production of pyrogenic materials and their applications as an effective immobilization and separation tools for wide range of xenobiotics can be innovative method in environmental management and waste assessment.

Pyrogenic Materials-Induced Immobilization of Eu in Aquatic and Soil Systems: Comparative Study

Crosslinked chitosan can potentially be used as a sorbent for removing pertechnetate anion $$^{ 9 9} {\text{TcO}}_{4}^{ - }$$
 from aqueous solutions. The chitosan was crosslinked with glutaraldehyde and prepared through chemical modification. The sorbent was characterized by BET-surface area and potentiometric titration. It was studied the influence of the contact time and the effect of pH on the sorption of pertechnetate anions. The selectivity for crosslinked chitosan for different cations with concentration above 1 × 10−3 mol dm−3 was in the order Fe3+ > Ca2+ > Na+ > Fe2+.

Sorption of technetium on glutaraldehyde crosslinked chitosan

The distribution of strontium between the milk components, i.e., serum, casein micelles, whey and hydroxyapatite was determined. The sorption on hydroxyapatite was investigated using batch method and radiotracer technique. The aqueous phase comprised of either milk or whey. The sorption of strontium on hydroxyapatite depended on the method of its preparation and on the composition of the aqueous phase. The sorption of strontium was increased with an increase of pH. The presence of citrate species resulted in decrease of the sorption of strontium on hydroxyapatite. The sorption of 85Sr on hydroxyapatite decreased with the increasing concentration of Ca2+ ions. Addition of Ca2+ ions to milk resulted in milk pH decrease. The decrease in pH value after calcium addition to milk is related to exchanges between added calcium and micellar H+. The average value of strontium sorption on casein micelles in milk with presence of hydroxyapatite was (47.3 ± 5.6) %. The average value of sorption of 85Sr on casein micelles in milk without the addition of hydroxyapatite was (68.9 ± 2.2) %.

Michal Galamboš

Papers

Adsorption of nickel on rhyolitic Slovak bentonites

Adsorption of nickel on andesitic bentonite Lieskovec

Pyrogenic Materials-Induced Immobilization of Eu in Aquatic and Soil Systems: Comparative Study

Sorption of technetium on glutaraldehyde crosslinked chitosan

Distribution of strontium in milk component