Evaluation of the adsorption process using activated bone char functionalized with magnetite nanoparticles

Performance and mechanism of simultaneous Sb(III) and Cd(II) removal from water by Fe-Mn binary oxide/bone char

A novel Fe-Mn binary oxide (FMBO)/bone char composite (FMBC) was synthesized and utilized to simultaneously adsorb Sb(III) and Cd(II) from aqueous phase in this study. The successful loading of Fe-Mn binary oxide on the bone char surface was revealed by the results of scanning electron microscope, X-ray diffraction patterns, and energy dispersive spectroscopy of FMBC. The FMBC exhibited remarkable ability of simultaneous removing Sb(III) and Cd(II) from aqueous, and the presence of Cd(II) enhanced Langmuir theoretical maximum adsorption capacity for Sb(III) significantly from 67.8 to 209.0 mg/g. Besides, FMBC could efficiently remove Sb(III) and Cd(II) in the wide initial pH range of 2-7. The influences of ionic strength, co-existing anions, humic acid, and temperature on the adsorption of Sb(III) and Cd(II), and the application potential of FMBC in actual groundwater were investigated. The main mechanisms of Sb(III) and Cd(II) adsorption onto FMBC involved redox, electrostatic interaction, surface complexation, ion exchange, and precipitation. The result of X-ray photoelectron spectroscopy and mapping spectrum analysis revealed that Mn(III) on FMBC played the key role in the Sb(III) oxidation, while FeOOH worked as the adsorption sites of FMBC. Meanwhile, the hydroxyapatite on FMBC also contributed to the removal of Cd(II). The presence of Cd(II) not only increased the positive charge on the surface of FMBC but also formed the Fe-Sb-Cd ternary complex, promoting the removal of Sb. This work provides valuable information for the application of FMBO/bone char as a cost-effective adsorbent to remediate co-pollution of Sb(III) and Cd(II) in aqueous environment.

Feasibility of magnetic nano adsorbent impregnated with activated carbon from animal bone waste: Application for the chromium (VI) removal

Chromium is the heavy metal which existing in the effluents cause extensive discomfort to the environmental components. Bone waste is widely generated in food processing industries and restaurants. It is now used by switching into activated carbon. By co-precipitation procedure, the activated carbon is coated with a nano adsorbent. The Fe₃O₄-BAC adsorbent potential was established in this study via several batch tests. The adsorbing adverts had super magnetic behavior, and the magnetization value was 22 emu/g. The SEM imaging of the Fe₃O₄-BAC shows an improved morphology of 100-446 nm, and the nanoparticles were monodispersed. The present investigation also delves into the study of system parameters on the removal of metal ions. Optimal adsorption has been found at the acidic pH at the contact time of 60min for the adsorbent amount of 5 g/L. Maximum capacity of adsorption by nano adsorbent was 27.86 mg/g. Thermodynamic and isotherm tests have established the process viability. In addition, the kinetic studies establish the inclination of the studied Fe₃O₄-BAC towards pseudo-first order models. Hence, Fe₃O₄-BAC could be potential adsorbent to remove chromium from an aqueous solution.

Engineered Magnetic Carbon-Based Adsorbents for the Removal of Water Priority Pollutants: An Overview

This review covers the preparation, characterization, and application of magnetic adsorbents obtained from carbon-based sources and their application in the adsorption of both inorganic and organic pollutants from water. Different preparation routes to obtain magnetic adsorbents from activated carbon, biochar, hydrochar, graphene, carbon dots, carbon nanotubes, and carbon nanocages, including the magnetic phase incorporated on the solid surface, are described and discussed. The performance of these adsorbents is analyzed for the removal of fluoride, arsenic, heavy metals, dyes, pesticides, pharmaceuticals, and other emerging and relevant water pollutants. Properties of these adsorbents and the corresponding adsorption mechanisms have been included in this review. Overall, this type of magnetic adsorbents offers an alternative for facing the operational problems associated to adsorption process in water treatment. However, some gaps have been identified in the proper physicochemical characterization of these adsorbents, the development of green and low-cost preparation methods for their industrial production and commercialization, the regeneration and final disposal of spent adsorbents, and their application in the multicomponent adsorption of water pollutants.

Batch and Packed Bed Column Study for the Removal of Cr (VI) and Ni (II) Using Agro-Industrial Wastes

The objective of this study was to prepare bio adsorbents from agro-industrial wastes from yam starch (YSR) and plantain (PSR) production for its use in the removal of Cr (VI) and Ni (II) in aqueous solution in batch and continuous packed-bed column systems. Bromatological analysis showed that the biomaterials are rich in cellulose, lignin, hemicellulose, and SEM micrographs that evidence a mesoporous structure characteristic of materials of lignocellulosic origin. FTIR evidenced functional groups such as hydroxyl, carbonyl, and methyl, possibly involved in the uptake of metal ions. EDS and FTIR analysis after adsorption confirmed that the retention of the metals on the surface of the adsorbent materials was successful. Cr (VI) and Ni (II) removal efficiencies above 80% were achieved using YSR and PSR in batch systems at the different conditions evaluated. The optimum conditions for removing Ni (II) on PSR were a bed height of 11.4 cm and a temperature of 33 °C, while for YSR, they were: 43 °C and 9 cm for temperature and bed height respectively. The variable with the most significant influence on the removal of Cr (VI) in a batch system on the two bio adsorbents was temperature. In contrast, the adsorbent dose and temperature are relevant factors for PSR Ni (II) removal. Therefore, the residues from the preparation of yam and plantain starch have high potential for removing heavy metals from wastewater and are presented as an alternative for their final disposal.

Characterization of Residual Biomasses and Its Application for the Removal of Lead Ions from Aqueous Solution

The removal of water pollutants has been widely addressed for the conservation of the environment, and novel materials are being developed as adsorbent to address this issue. In this work, different residual biomasses were employed to prepare biosorbents applied to lead (Pb(II)) ion uptake. The choice of cassava peels (CP), banana peels (BP), yam peels (YP), and oil palm bagasse (OPB) was made due to the availability of such biomasses in the Department of Bolivar (Colombia), derived from agro-industrial activities. The materials were characterized by ultimate and proximate analysis, Fourier Transform Infrared Spectroscopy (FTIR), Brunauer-Emmett-Teller analysis (BET), Scanning Electron Microscopy (SEM), and Energy Dispersive X-Ray Spectroscopy (EDS) in order to determine the physicochemical properties of bioadsorbents. The adsorption tests were carried out in batch mode, keeping the initial metal concentration at 100 ppm, temperature at 30 °C, particle size at 1 mm, and solution pH at 6. The experimental results were adjusted to kinetic and isotherm models to determine the adsorption mechanism. The remaining concentration of Pb(II) in solution was measured by atomic absorption at 217 nm. The functional groups identified in FTIR spectra are characteristic of lignocellulosic materials. A high surface area was found for all biomaterials with the exception of yam peels. A low pore volume and size, related to the mesoporous structure of these materials, make these bioadsorbents a suitable alternative for liquid phase adsorption, since they facilitate the diffusion of Pb(II) ions onto the adsorbent structure. Both FTIR and EDS techniques confirmed ion precipitation onto adsorbent materials after the adsorption process. The adsorption tests reported efficiency values above 80% for YP, BP, and CP, indicating a good uptake of Pb(II) ions from aqueous solution. The results reported that Freundlich isotherm and pseudo-second order best fit experimental data, suggesting that the adsorption process is governed by chemical reactions and multilayer uptake. The future prospective of this work lies in the identification of alternatives to reuse Pb(II)-contaminated biomasses after heavy metal adsorption, such as material immobilization.