RESUMO

The high levels of heavy metals contained in residual water and the pollution generated by a large amount of unexploited agro-industrial waste are a serious problem for the environment and mankind. Therefore, in the present work, with the aim of treating and reducing the pollution caused by heavy metal ions (Pb, Cd, Zn and Cu), activated carbons (ACs) were synthesized from sugarcane bagasse (SCB) and orange peel (OP) by means of physical - chemical activation method in an acid medium (H3PO4, 85 wt%) followed by an activation at high temperature (500 and 700 °C). Thereafter, these materials were used to produce carbon foams (CF) by the replica method and to evaluate their adsorbent capacity for the removal of heavy metals from synthetic water. XRD, FTIR, DLS, BET, Zeta Potential (ζ), SEM-EDS and AAS were used to investigate their structures, surface area, pore size, morphology, and adsorption capacity. The results show that as-prepared CF have a second level mesoporous structure and AC present a micro-mesoporous structure with a pore diameter between 3 and 4 nm. The experimental adsorption capacities of heavy metals showed that the CF from OP present a better elimination of heavy metals compared to the AC; exhibiting a removal capacity of 95.2 ± 3.96% (Pb) and 94.7 ± 4.88% (Cu) at pH = 5. The adsorption values showed that the optimal parameters to reach a high metal removal are pH values above 5. In the best of cases, the minimum remaining concentration of lead and copper were 2.4 and 2.6 mg L-1, respectively. The experimental data for carbon adsorbents are in accordance with the Langmuir and BET isotherms, with R2 = 0.99 and the maximum homogenous biosorption capacity for lead and copper was Qmax = 968.72 and 754.14 mg g-1, respectively. This study showed that agro-industrial wastes can be effectively retrieved to produce adsorbents materials for wastewater treatment applications.

Assuntos

Citrus sinensis , Metais Pesados , Saccharum , Poluentes Químicos da Água , Adsorção , Biomassa , Celulose , Cobre , Concentração de Íons de Hidrogênio , Resíduos Industriais , Íons , Cinética , Chumbo , Metais Pesados/análise , Água/química , Poluentes Químicos da Água/análise

RESUMO

Cellulose nanocrystals (CNCs) were isolated from two-agroindustrial wastes: sugarcane bagasse (SCB) and pinewood sawdust (PWS), to analyze their chemical, structural, morphological, and proton conduction properties in dependence of the synthesis parameters. In both sources, the isolated CNCs correspond to the monoclinic phase of cellulose type I and II. For SCB, the smallest CNCs were isolated, in a range of 3-10 nm, with 5 wt.% of NaOH and 60 °C of acid hydrolysis. PWS displayed the smallest sizes at 75 °C and 10 wt.% NaOH (40-110 nm). Membrane characterization suggests that isolated CNCs, between 75 and 90 °C of acid hydrolysis and 10 wt.% NaOH from both SCB and PWS sources, displayed an important increase in the proton conductivity, 1.23(±0.61)×10-5 and 9.26 (±0.24)×10-5 S-m-1, respectively. Thus, with proper synthesis conditions, CNCs can be potentially used as based element to obtain other proton conductor materials to fabricate PEMs.

RESUMO

Structural, compositional, morphological and electrochemical characterization are important to determinate the influence of platinum in the methanol oxidation in alkaline media. These data and analysis support the research article catalytic performance of alloyed PtxPd1-x nanostructures supported on Vulcan XC-72R for the methanol oxidation in alkaline medium [1]. The data here presented included changes in the chemical composition, structure and microstructure. Also, complement data of cyclic voltammograms during activation in alkaline media as well as in presence of 1 M CH3OH to observe CO tolerance and Electrochemical Impedance Spectroscopy measurements at two different overpotentials (0.2 and 0.3 mV) on the onset potential for methanol electro-oxidation are published in this paper. The data can be used as a reference to determinate the effect of added different amounts of Pd to Pt/C catalysts, using an organometallic compounds method and octylamine as stabilizer. The data provided in this article have not been previously published and are available to enable critical or extended analyses.

RESUMO

The data set presented here offers evidence of the elemental composition related to a SEM micrograph of [Mn5(PO3(OH))2(PO4)2⋅4H2O] (MnPhos) powders, known as hurealite, and synthesized by the reflux method. In addition, it contains additional information of the glass transition, melting and decomposition temperatures and their weight loss percent of coatings based on MnPhos incorporated into waterborne poly(urethane) (WPU). These data are complementing of the article "Corrosion investigation of new hybrid organic/inorganic coatings for carbon steel substrates: electrochemical and surface characterizations".

RESUMO

The data presented in this article are related to the research previously published "improvement of adhesion and barrier properties of biomedical stainless steel by deposition of YSZ coatings using RF magnetron sputtering". It contains the structural, morphological, compositional and electrochemical characterization of bare AISI 316L substrate which was used as a substrate to coat with yttria-stabilized zirconia (YSZ). The chemical composition and topography analyses from X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES) and micrographs from atomic force microscopy (AFM) as well as the roughness value of the YSZ-sputtered coating on AISI 316L substrates are presented as complementary data of the article.

RESUMO

The treatment of agroindustrial residues is an alternative to waste management and obtain products with added value. In this article, we describe the confocal microscopy images, the microbiological data, policosanol content and color measurement linked to the paper "production of dietary fibers from sugarcane bagasse and sugarcane tops using microwave - assisted alkaline treatments". The data contain photographs after elaboration of noodles-type pasta and chapatti-type fermented bread; the confocal laser scanning micrographs, before and after including sugarcane bagasse and sugarcane tops fibers in foods. Microbiological analyses of total coliforms, molds and yeasts, and aerobic mesophiles were also presented according to Mexican Standard NOM- 247-SSA1-2008 which confirmed that the food is safe for human consumption. The data provided in this article have not been previously published and are available to enable critical or extended analyses.

RESUMO

These data display evidence of the fracture through the morphologies and the topographical features as well as roughness data of different ratios of R(recycled)-PET/PLA, PET(virgin)/PLA, PET(virgin)/Chitosan and R(recycled)-PET/chitosan. Also, data of the morphologies after degradation under accelerated weathering test and degradation mechanisms are revealed. The data supplement the article "Comparative assessment of miscibility and degradability on PET/PLA and PET/chitosan blends".

RESUMO

Structural and microstructural characterization combined with vibrational, rotational modes are quite important to determinate reduction degree during synthesis of reduced graphene oxide. These data and analysis support the research article "Electrochemical alternative to obtain reduced graphene oxide by pulse potential: effect of synthesis parameters and study of corrosion properties" (López-Oyama et al., 2018). The data and analysis presented here included raw data for selected reduction potentials (V SCE) and different temperatures values (°C). Transmission electron microscopy (TEM) images of the exfoliated graphite are shown to corroborate the effect of the applied voltage to obtain electrochemically reduced graphene oxide (ERGO) on commercial 304L stainless steel (304L SS). The data provided in this article has not been previously published and are available to enable critical or extended analyses.