Equilibrium study of binary mixture biosorption of Cr(III) and Zn(II) by dealginated seaweed waste: investigation of adsorption mechanisms using X-ray photoelectron spectroscopy analysis

Biosorption: A Review of the Latest Advances

Biosorption is a variant of sorption techniques in which the sorbent is a material of biological origin. This technique is considered to be low cost and environmentally friendly, and it can be used to remove pollutants from aqueous solutions. The objective of this review is to report on the most significant recent works and most recent advances that have occurred in the last couple of years (2019–2020) in the field of biosorption. Biosorption of metals and organic compounds (dyes, antibiotics and other emerging contaminants) is considered in this review. In addition, the use and possibilities of different forms of biomass (live or dead, modified or immobilized) are also considered.

Lithothamnium calcareum (Pallas) Areschoug seaweed adsorbs aflatoxin B1 in vitro and improves broiler chicken's performance

This study aimed to evaluate the aflatoxin B₁ (AFB₁) adsorption capacity of the seaweed Lithothamnium calcareum in vitro and to prevent aflatoxicosis in broiler chickens. In vitro adsorption assays were performed at a single AFB₁ concentration (1 μg/mL) and four seaweed concentrations (0.50, 1, 1.5 and 2 mg/mL) at pH 3 and pH 6. The maximum adsorption was obtained at the lowest seaweed content (0.62 and 0.78 μg/mg). Male broiler chickens (256) were housed in metallic cages. Experimental diets were T1 (control), 18 μg/kg AFB₁; T2, 18 μg/kg AFB₁ and 0.2% L. calcareum (2.0 kg/ton); T3, 1018 μg/kg AFB₁; and T4, 1018 μg/kg AFB₁ and 0.2% L. calcareum. Performance parameters (live weight, weight gain and feed conversion rate) improved when seaweed was applied. The aspartate-aminotransferase and alanine-aminotransferase levels tend to decrease in birds receiving only seaweed, also the uric acid levels reduced significantly (P ˂ 0.05), while birds receiving only AFB₁ increased the biochemical parameter levels. The livers from animals fed with AFB₁ showed histopathological alterations with disorganization of periportal hepatocytes, necrosis with multifocal coagulation and mild fat degeneration; the livers from T4 had normal appearance. Lithothamnium calcareum was able to prevent aflatoxicosis in broiler chickens and also improved their zootechnical performance.

Removal of propranolol hydrochloride by batch biosorption using remaining biomass of alginate extraction from Sargassum filipendula algae

Propranolol hydrochloride is a popular anti-hypertensive and pollutant of emerging concern because of potential ecological risks to aquatic environment. In this study, biosorption is presented as an advanced approach for propranolol uptake from aqueous media. The remaining biomass of alginate extraction from brown seaweed (RSF) was tested as biosorbent owing to its key binding sites, namely carboxyl and hydroxyl functional groups. The high 93% removal efficiency achieved consolidates RSF as effective biosorbent for propranolol environmental remediation and values this waste material, which has been largely discarded in industry after alginate extraction. RSF had morphology, porosity, chemical composition, and thermal behavior characterized prior and post to application in propranolol biosorption. Molecular sieving effects were excluded by assessing the molecular geometry of propranolol. The kinetics was inspected by both rate laws and mass transfer models. Langmuir, Freundlich, and Dubinin-Radushkevich equations were tested for experimental isotherms. Propranolol biosorption onto RSF was further inspected by thermodynamic parameters, including isosteric heat.

Upon designing carboxyl methylcellulose and chitosan-derived nanostructured sorbents for efficient removal of Cd(II) and Cr(VI) from water

Considering that the hazardous heavy metal ions like Cd(II) and Cr(VI) are widely present in the environment, nowadays employing easy-to-handle adsorption-oriented processes are feasible choices towards efficient remediation of Cd(II) and Cr(VI) from aqueous systems. Herein we developed a novel amino-functionalized bead with cost-effectiveness, high sorption capacity and fast sorption kinetics to remove Cd(II) and Cr(VI) from aqueous solution. The carboxyl methylcellulose and chitosan-derived nanostructured sorbents synthesis were mainly through chitosan and dopamine self-polymerization, doped in sodium carboxymethyl cellulose, and glutaraldehyde cross-linking. The pH value, initial concentration and contact time were investigated. Experimental data were commendably described by Freundlich isotherm and Pseudo-second-order model. The maximum adsorption capacities of Cd(II) and Cr(VI) obtained from the experimental data were 470.0 mg/g and 347.0 mg/g, respectively. The adsorbents were collaboratively characterized by FT-IR, SEM, TGA, XPS, etc., and the adsorbent basically exhibited high complexation ability to Cd(II) and showed strong electrostatic effect with Cr(VI) under acidic conditions. The recycling characteristics suggested that it possesses an outstanding recyclability. The adsorbent may have a potential as high-value biological adsorbent to remove heavy metals and it deserves further research into the practical application.

Competitive biosorption of Cu2+ and Ag+ ions on brown macro-algae waste: kinetic and ion-exchange studies

The application of biosorption operation has gained attention in the removal and retrieval of toxic metal ions from water bodies. Wastewater from industrial activity generally presents great complexity due to the coadsorption of cations to the inactive biomass binding sites. In this work, the competitive biosorption of Cu(II) and Ag(I) ions was studied in batch systems. A kinetic study applying a non-acidified and acidified waste of Sargassum filipendula in equimolar and non-equimolar metal samples was carried out and the acidified biosorbent was selected due to higher removal rates and selectivity of silver ions. The assays were performed with 2 g L^-1 of biosorbent concentration at 25 °C for 12 h and pH was controlled at around 5.0. Copper presented higher affinity for the biosorbent and a fast biosorption kinetic profile, while silver equilibrium times exhibited dependence on the copper concentration. External diffusion is the rate-limiting step in Cu(II) ion removal and it might also limit the kinetic rates of Ag(I) ions with intraparticle diffusion, depending on the initial concentration of metal cations. The ion-exchange mechanism is evidenced and complexation and electrostatic attraction mechanisms might be suggested, explained by simultaneous chemisorption and physisorption processes during the operation. Calcium and sodium were released in considerable amounts by the ion-exchange mechanism. Characterization analyses confirmed the role of several functional groups in the competitive biosorption accompanied by a homogenous covering of both metal ions on the surface of the particles. Particle porosity analyses revealed that the material is macroporous and an appreciable amount of macropores are filled with metal cations after biosorption.