Valorization of keratin biofibers for removing heavy metals from aqueous solutions

Four common waste keratin biofibers (human hair, dog hair, chicken feathers, and degreased wool) have been used as biosorbents for the removal of heavy metal ions from aqueous solutions. Different parameters of the biosorption processes were optimized in batch systems. For multiple-metal systems, consisting of a mixture of eight metal ions [Cr(III), Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and Pb(II)], the total metal biosorption increased in the order: degreased wool¿>¿chicken feathers¿>¿human hair¿>¿dog hair. From the kinetic models tested, the pseudo-second-order model provided better results. Furthermore, biosorption isotherms of Pb(II) with the different keratin biofibers fitted the Langmuir model. Surface morphology of the biosorbents were analyzed before and after the sorption using Fourier transform infrared spectroscopy and scanning electron microscopy. The keratin biofibers tested are potentially good sorbents of metal ions, with degreased wool and chicken feathers being the more efficient onesPostprint (author's final draft

Alternative methods for the wool wax extraction from wool scouring wastes

Las fibras de lana, tras obtenerlas de las ovejas y antes de ser procesadas industrialmente, han de ser lavadas. Este proceso genera residuos altamente contaminantes que pueden obtenerse en dos formas diferentes, una fase líquida y una fase sólida. Ambas fases contienen, entre otros, una gran cantidad de la grasa generada por las ovejas y que se puede recuperar y purificar para obtener lanolina, un producto de alto valor industrial. Para evaluar la cantidad de grasa contenida en dichos efluentes, la técnica más extendida en los laboratorios es la extracción por Soxhlet, la cual consume tiempo y disolventes orgánicos pero obteniendo altos porcentajes de recuperación. En el presente trabajo se compara el porcentaje de recuperación de la cera de lana de efluentes industriales mediante técnicas alternativas a la tradicional (Microondas, Soxhlet automatizado y Fluidos Supercríticos) obteniendo recuperaciones del 100%, reduciendo el tiempo de análisis, el consumo de disolvente y la generación de residuos.Wool fibers have to be properly washed out before being processed into fabrics. This scouring process generates high pollutant wastes in two forms, a liquid phase and a solid phase. Both phases contain a large amount of the grease (wool wax) generated by the animal which may be recovered and purified to obtain lanolin, a highly valued product. To evaluate the amount of grease in such wastes, Soxhlet extraction with organic solvent is the technique more widely used in laboratories worldwide as it provides a high grease recovery although it is a time and solvent consuming technique. The present work compares alternative extraction techniques to the Soxhlet extraction (Microwave, automated Soxhlet and Supercritical Fluids) recovering 100% of the grease, reducing the time of analysis, the solvent consumption and the waste generation

Use of chemically treated human hair wastes for the removal of heavy metal ions from water

Human hair is considered a ubiquitous waste product and its accumulation can cause environmental problems. Hence, the search for alternatives that take advantage of this waste as a new raw material is of interest, and contributes to the idea of the circular economy. In this study, chemically modified human hair was used as a low cost biosorbent for the removal of heavy metal ions from aqueous solutions. The effect of the contact time, the pH, and the biosorbent concentration on the biosorption process were investigated. Kinetic modeling indicated that the pseudo-second order kinetic equation fitted well with R2> 0.999. Furthermore, the equilibrium data fitted the Langmuir adsorption isotherm at 295 K resulting insaturation concentrations of9.47×10-5, 5.57×10-5, 3.77×10-5,and3.61×10-5mol/g for the sorption of Cr(III), Cu(II), Cd(II), and Pb(II), respectively. The biosorption process did not change the chemical structure and morphology of the hair, which was shown by FTIR and SEM. In addition, desorption experiments prove that 0.1 mol/L EDTA solution is an efficient eluent for the recovery of Pb(II) from the treated human hair. To summarize, treated human hair showed satisfactory biosorption capacity and can be considered as an effective biosorbent for the treatment of waterwith a low concentration of heavy metal ionsPostprint (published version

Supercritical fluid extraction as a clean-up method for the extraction of pesticides from wool wax. A preliminary approach

Este trabajo es un estudio preliminar para el desarrollo de un metodo de extraccion de pesticidas directamente de las muestras de cera mediante extraccion con fluido supercritico. La novedad del estudio consiste en la extraccion directa de los pesticidas de la cera de lana cruda sin ninguna limpieza previa, cuando muchos autores han considerado casi imposible la extraccion directa.The work presented is a preliminary study for the development of a method for the extraction of pesticides from wax samples by means of superficial fluid extraction. The novelty of the study is the direct extraction of the pesticides from raw wool wax without any cleanup, as direct extraction has been considered almost impossible by many authors

Biological treatment of a textile effluent after electrochemical oxidation of reactive dyes

Electronic version of an article published as "Water environment research", vol.82, no.2, 2010,p.176-182. DOI No:10.2175/106143009X447902In this work, a synthetic textile effluent containing a reactive dye (C.I. Reactive Orange 4) was treated in an electrochemical cell with titanium covered by platinum oxide (Ti/PtOx) electrodes to remove color. The discolored effluent was mixed with other textile mill process effluents (scouring, bleaching, washing, etc.), according to the rate of each effluent in the mill, and was submitted to biological treatment (activated sludge plant). Two biological plants were run simultaneously to evaluate the influence of oxidant products generated during the electrochemical treatment. The final chemical oxygen demand (COD) removal in both plants was 65 to 72%. The yield of the activated sludge plants was not affected by the addition of 10% of the discolored dyeing effluent (even when oxidants products were not removed), which indicates that the previous electrochemical treatment do not produce inhibition effects on the biological plant. However, in the case of direct addition of the discolored effluent, the biological treatment plant required a longer adaptation period. In addition, the electrolytic respirometry tests showed that all the biodegradable organic matter was removed, which implies that the yield in organic matter removal was the maximum possible for this type of treatment.Peer ReviewedPostprint (published version

Validated method for polystyrene nanoplastic separation in aqueous matrices by asymmetric-flow field flow fraction coupled to MALS and UV-Vis detectors

Altres ajuts: acords transformatius de la UABPlastics with nanosize (nanoplastics, NPLs) must be characterized, since they can be toxic or act as carriers of organic and inorganic pollutants, but there is a lack of reference materials and validated methods in the nanosize range. Therefore, this study has focused on the development and validation of a separation and size characterization methodology of polystyrene latex nanospheres, by using an asymmetric-flow field flow fraction system coupled to multi-angle light scattering and ultraviolet-visible detectors (AF4-MALS-UV). Hence, this work presents a fully validated methodology in the particle size range 30 to 490 nm, with bias between 95 and 109%, precision between 1 and 18%, LOD and LOQ below 0.2 and 0.3 µg respectively, except for 30-nm standard, for both detectors, and showing stable results for 100 analyses

Trace cisplatin and carboplatin removal by 3-mercaptopropionic acid and L-cysteine functionalized sponges : Adsorption behaviour and mechanism

Altres ajuts: acords transformatius de la UABThis study presents functionalized open-celled cellulose Metalzorb® sponge (Sponge) with 3-mercaptopropionic acid (MPA) and L-Cysteine (Cys), and the resulting MPA@Sponge and Cys@Sponge showed significantly improved removal efficiency towards trace cisplatin and carboplatin against Sponge. MPA@Sponge achieved maximum removal of 88.9 ± 0.5% for cisplatin and 85.2 ± 0.4% for carboplatin, while Cys@Sponge achieved maximum removal of 75 ± 2% and 59 ± 1%. In contrast, Sponge only achieved removal of 29 ± 4% and 4 ± 1%, respectively. It suggests that thiol groups serve as favourable binding sites for Pt complexation. Carboplatin exhibits lower adsorption compared to cisplatin due to its limited hydration. However, the presence of Cl in stock and high temperature facilitate the hydration and the formation of active derivatives of carboplatin, thereby enhancing its adsorption. The rapid adsorption processes of cisplatin and carboplatin are well described by the pseudo-second-order kinetic model involving diffusion and chemisorption. The results from adsorption isotherms revealed a monolayer adsorption that aligns with the principles proposed by the Langmuir model. High temperature significantly enhances the adsorption, and the positive enthalpies indicate that the binding of Pt with thiol groups is endothermic process. X-ray absorption spectroscopy measurements at the Pt L-edge revealed a similar coordination environment of the adsorbed Pt on both functionalized adsorbents, which can be attributed to the formation of four Pt-S bonds during the adsorption. To assess the validity of the adsorption results under realistic medium conditions, an adsorption study was carried out by using diluted urine spiked with trace platinum cytostatic drugs to simulate hospital wastewater. 90.2 ± 0.3% of cisplatin and 77.0 ± 0.2% of carboplatin was effectively removed by MPA@Sponge from diluted urine

Comparative study on removal of platinum cytostatic drugs at trace level by cysteine, diethylenetriamino functionalized Si-gels and polyethyleneimine functionalized sponge : Adsorption performance and mechanisms

Altres ajuts: acords transformatius de la UABTo efficiently remove trace Pt-based cytostatic drugs (Pt-CDs) from aqueous environments, a comparative investigation was conducted on the adsorption behavior of three commercial adsorbents including cysteine-functionalized silica gel (Si-Cys), 3-(diethylenetriamino) propyl-functionalized silica gel (Si-DETA) and open-celled cellulose MetalZorb® sponge (Sponge). The research on the adsorption of cisplatin and carboplatin encompasses investigations of pH dependence, adsorption kinetics, adsorption isotherms, and adsorption thermodynamics. The obtained results were compared with those of PtCl42− to better understand the adsorption mechanisms. The adsorption of cisplatin and carboplatin by Si-Cys was significantly better than Si-DETA and Sponge, which suggested that in chelation-dominated chemisorption, thiol groups provided high-affinity sites for Pt(II) complexation. Adsorption of the anion PtCl42− was more pH dependent and generally superior to that of cisplatin and carboplatin, benefiting from the contribution of ion association with protonated surfaces. The removal process of aqueous Pt(II) compounds occurred by the hydrolysis of complexes in solution and subsequent adsorption, and the specific adsorption process was explained by the synergistic action of ion association and chelation mechanisms. The rapid adsorption processes involving diffusion and chemisorption were well described by pseudo-second-order kinetic model. The isotherm studies suggested monolayer adsorption, consistent with the Langmuir model. Indicated from the adsorption enthalpy results, the chelation of cisplatin and carboplatin with thiol groups was an endothermic reaction, while the adsorption of PtCl42− was exothermic. At 343 K, Si-Cys achieved 98.5 ± 0.1 % (cisplatin) and 94.1 ± 0.1 % (carboplatin) removal. To validate the obtained findings, the described process was applied to urine samples doped with Pt-CDs as analog of hospital wastewaters and the removal was very efficient, ranging from 72 ± 1 % to 95 ± 1 %, when using Si-Cys as adsorbent, although limited matrix effects were observed

Taking advantage of hyperspectral imaging classification of urinary stones against conventional infrared spectroscopy

The analysis of urinary stones is mandatory for the best management of the disease after the stone passage in order to prevent further stone episodes. Thus the use of an appropriate methodology for an individualized stone analysis becomes a key factor for giving the patient the most suitable treatment. A recently developed hyperspectral imaging methodology, based on pixel-to-pixel analysis of near-infrared spectral images, is compared to the reference technique in stone analysis, infrared (IR) spectroscopy. The developed classification model yields >90% correct classification rate when compared to IR and is able to precisely locate stone components within the structure of the stone with a 15 µm resolution. Due to the little sample pretreatment, low analysis time, good performance of the model, and the automation of the measurements, they become analyst independent; this methodology can be considered to become a routine analysis for clinical laboratories

A new source of representative secondary PET nanoplastics. Obtention, characterization, and hazard evaluation

Acord transformatiu CRUE-CSICAltres ajuts: Juan de la Cierva IJC2020-2686IMicro and nanoplastics (MNPLs) are emergent environmental pollutants requiring urgent information on their potential risks to human health. One of the problems associated with the evaluation of their undesirable effects is the lack of representative samples, matching those resulting from the environmental degradation of plastic wastes. To such end, we propose an easy method to obtain polyethylene terephthalate nanoplastics from water plastic bottles (PET-NPLs) but, in principle, applicable to any other plastic goods sources. An extensive characterization indicates that the proposed process produces uniform samples of PET-NPLs of around 100 nm, as determined by using AF4 and multi-angle and dynamic light scattering methodologies. An important point to be highlighted is that to avoid the metal contamination resulting from methods using metal blades/burrs for milling, trituration, or sanding, we propose to use diamond burrs to produce metal-free samples. To visualize the toxicological profile of the produced PET-NPLs we have evaluated their ability to be internalized by cells, their cytotoxicity, their ability to induce oxidative stress, and induce DNA damage. In this preliminary approach, we have detected their cellular uptake, but without the induction of significant biological effects. Thus, no relevant increases in toxicity, reactive oxygen species (ROS) induction, or DNA damage -as detected with the comet assay- have been observed. The use of representative samples, as produced in this study, will generate relevant data in the discussion about the potential health risks associated with MNPLs exposures