20 research outputs found
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Comparison of acidic leaching using a conventional and ultrasound-assisted method for preparation of magnetic-activated biochar
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Composite of methyl polysiloxane and avocado biochar as adsorbent for removal of ciprofloxacin from waters
Two carbon composite materials were prepared by mixing avocado biochar and methyl polysiloxane (MK). Firstly, MK was dissolved in ethanol, and then the biochar was added at different times. In sample 1 (R1), the time of adding biochar was immediately after dissolving MK in ethanol, and in sample 2 (R2), after 48 h of MK dissolved in ethanol. The samples were characterized by nitrogen adsorption/desorption measurements obtaining specific surface areas (SBET) of 115 m2 gâ1 (R1) and 580 m2 gâ1 (R2). The adsorbents were further characterized using scanning electron microscopy, FTIR and Raman spectroscopy, adsorption of vapors of n-heptane and water, thermal analysis, Bohem titration, pHpzc, and C H N elemental analysis. R1 and R2 adsorbents were employed as adsorbents to remove the antibiotic ciprofloxacin from the waters. The t1/2 and t0.95 based on the interpolation of Avrami fractional-order were 20.52 and 246.4 min (R1) and 14.00 and 157.6 min (R2), respectively. Maximum adsorption capacities (Qmax) based on the Liu isotherm were 10.77 (R1) and 63.80 mg gâ1 (R2) for ciprofloxacin. The thermodynamic studies showed a spontaneous and exothermic process for both samples, and the value of ÎH° is compatible with physical adsorption
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Preparation of hybrids of wood sawdust with 3-aminopropyl-triethoxysilane. Application as an adsorbent to remove reactive blue 4 dye from wastewater effluents
Background: Biomass-based materials present low sorption capacity. In order to overcome this disadvantage, chemical modification of these materials is required.
Methods: Hybrids of biomass-based materials were obtained by reacting (25%-200% weight) 3-aminopropyl-triethoxysilane (APTES) with the biomass Ayous wood sawdust (AW), obtaining the hybrid materials [email protected], [email protected], [email protected], [email protected], and [email protected], that were characterized by hydrophobic/hydrophilic balance, CHN elemental analysis, surface area, TGA, FTIR, and pHpzc.
Significant findings: For screening purposes, the five materials were tested as adsorbents to remove reactive blue 4 (RB-4) from water. The results showed that [email protected] attained the maximum removal of RB-4. The kinetics and equilibrium data were suitably fitted by the nonlinear General-order kinetic (GO) and Liu equilibrium adsorption models. The maximum amount adsorbed of RB-4 dye was 415.1 mg g â 1 using [email protected] (50 °C). An increase in the Qmax value of [email protected] concerning unmodified AW attained up to 21.6 times. The ÎG° and ÎH° indicated that the adsorption processes of RB-4 onto adsorbents are endothermic and spontaneous, and the magnitude of enthalpy of adsorption (25.10 kJ molâ1) is compatible with the electrostatic attraction mechanism. The adsorbentsâ applicability for treating simulated dye effluents showed an excellent efficiency attaining 98.66% removal of the effluent
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Removal of enalapril maleate drug from industry waters using activated biochar prepared from Butia capitata seed. Kinetics, equilibrium, thermodynamic, and DFT calculations
Porous biochar was fabricated from Butia capitata (Bc) seed, which was used to uptake enalapril maleate from synthetic wastewater. Activated biochars were fabricated by blending Bc and ZnCl2 at 1:1 (BcB-1.0) or 1:1.5 (BcB-1.5) proportions and furtherly pyrolyzed at 600 °C. The elemental analysis, Boehm titration, hydrophobic balance ratio, FTIR, TGA, and N2 isotherm characterized the carbon-based materials. They presented a hydrophilic behavior with diverse polar groups on their surface. BcB-1 and BcB-1.5 biochars have a total pore volume of 0.392 and 0.492 cm3 gâ1 and a surface area of 1267 and 1520 m2/g, respectively. The kinetics and isothermal data were adequately adjusted to the fractal-like pseudo-second-order and Liu models. The employment of BcB-1.0 and BcB-1.5 for treating synthetic wastewater containing high levels of pollutants had elevated efficiency in their removals (up to 99.06%). We also conducted a DFT computational study, density functional theory (DFT), to examine the interactions between enalapril and a graphitic domain of biochar by using these calculations, the most stable configuration presented interaction energy of â88.7 kJ molâ1 implies a face-to-face ÏâÏ stacking interaction involving the enalapril phenyl segment and an aromatic ring of the graphitic domain, as well as London dispersion arising from the proximity of ethoxy/pyrrolidine to biochar carbon atoms, with interatomic distances of 3.31 Ă
for the former and 3.60 Ă
/3.48 Ă
for the latter. Also, the DFT calculations agreed with the thermodynamic data calculated from the isotherms (283â318 K)