RESUMO
Packaging used for beverages, such as soft drinks, juices, and beers, is widely consumed worldwide. The manufacture of this packaging involves energy consumption, even when made with recycled material. The sum of all energies required to produce the packaging is considered the incorporated or embodied energy. In this work, the embodied energy used to manufacture six common types of beverage packaging was analyzed. For this purpose, the average percentage of material recycling in Brazil and the United States of America (USA) was considered since the energy incorporated is quite different when recycling is used. A calculation methodology was developed to estimate the embodied energy in each type of packaging in Brazil and the USA. For a more appropriate comparison, the embodied energy per volume was calculated. Comparing the embodied energy per volume, aluminum packaging, when mostly recycled, is the packaging that has the lowest embodied energy per liter of beverage. This study highlights the importance of recycling to produce packaging with less embodied energy and opens perspectives for environmentally more favorable attitudes regarding the choice of beverage packaging materials.
Assuntos
Bebidas , Embalagem de Produtos , Brasil , Bebidas Gaseificadas , Reciclagem , Estados UnidosRESUMO
The presence of pharmaceuticals in wastewater resulting from human activities has driven researchers to explore effective treatment methods such as adsorption using activated carbon (AC). While AC shows promise as an adsorbent, further studies are essential to comprehend its entire interaction with pharmaceuticals. This article investigates the adsorption of potassium diclofenac (PD) onto AC using experimental and modeling approaches. Batch adsorption studies coupled with Fourier transform infrared spectroscopy (FTIR) were employed to clarify the adsorption mechanism of PD on AC. Various kinetic and isotherm adsorption models were applied to analyze the adsorbent-adsorbate interaction. The kinetics were best described by Avrami's fractional order (AFO) nonlinear model. Also, the intraparticle diffusion (IP) model reveals a three-stage adsorption process. The experimental equilibrium data fitted well with the three-parameter nonlinear Liu model, indicating a maximum adsorption capacity (Qmax) of 88.45 mg g-1 and suggesting monolayer or multilayer adsorption. Thermodynamic analysis showed favorable adsorption (ΔG° < 0), with an enthalpy change (ΔH° = -30.85 kJ mol-1) characteristic of physisorption involving hydrogen bonds and π-π interactions. The adsorption mechanism was attributed to forming a double layer (adsorbate-adsorbent and adsorbate-adsorbate).
Assuntos
Carvão Vegetal , Diclofenaco , Poluentes Químicos da Água , Diclofenaco/química , Adsorção , Carvão Vegetal/química , Poluentes Químicos da Água/química , Cinética , Termodinâmica , Espectroscopia de Infravermelho com Transformada de Fourier , Águas Residuárias/química , Carbono/químicaRESUMO
The rise of contaminants of emerging concern in water-resources due to human activities has driven research toward wastewater treatment, specifically adsorption. The utilization of woody biomass for biochar production in adsorption has shown promise due to its high availability. This study shows the preparation of magnetic biochars (MB) from waste black wattle sawdust, utilizing ZnCl2 and NiCl2 (proportions: 1:0.5:0.5 = MB-0.5 and 1:1:1 = MB-1) as activating and magnetic agents. Synthesized via microwave-assisted-pyrolysis, MB boasts a high surface area (up to 765 m2.g-1) and functional groups, enhancing metoprolol medicine adsorption. Nonlinear kinetic and isothermal models were tested; the Avrami fractional-order kinetic model and Liu's isothermal model provided the best fits for experimental data. Thermodynamics and spectroscopic studies revealed spontaneous and exothermic adsorption processes, with physisorption magnitude and dominance of hydrogen-bond and π-π-interactions. MB can be easily extracted from an aqueous medium using magnetic fields, while adsorption capacity could be regenerated through green solvent elution.
RESUMO
This study presents the extraction of antibiotic amoxicillin (AMX) from aqueous solution employing activated carbons (AC) from olive biomass (OB). Two AC were prepared using ZnCl2 (activator agent), and a conventional muffle furnace (ACF) or microwave oven (ACMW). The structure, morphology, and textural properties from both AC were analyzed by scanning electron microscope (SEM), pH of point-zero-charge (pHPZC), infrared spectroscopy (FTIR), and N2 adsorption/desorption isotherms. AC with mesoporous structures rich in oxygenated groups and high specific area (as high as 1742 m2 g-1) were helpful for the efficient and fast adsorption of AMX. The Avrami kinetic nonlinear equation showed the best fitting for the empirical data when related to the pseudo-1st and pseudo-2nd order. The isothermal experimental data followed the Liu nonlinear model, displaying at 25 °C the maximum sorption capacity of 237.02 and 166.96 mg g-1 for the ACF and ACMW, respectively. An adsorption test with synthetic hospital effluent was carried out to evaluate the possibility of applying both adsorbents in wastewater purification. The purification efficiency was up to 94.4% and 91.96% for ACF and ACMW, respectively. Therefore, the AC obtained from OB (containing a mixture of seed, pulp, and olive peel) has a high potential for application in removing emerging contaminants from the wastewater.