Use of natural clays as sorbent materials for rare earth ions: materials characterization and set up of the operative parameters

Two mineral clays of the montmorillonite group were tested as sorbents for the removal of Rare Earths (REs) from liquid solutions. Lanthanum and neodymium model solutions were used to perform uptake tests in order to: (a) verify the clays sorption capability, (b) investigate the sorption mechanisms and (c) optimize the experimental parameters, such as contact time and pH. The desorption was also studied, in order to evaluate the feasibility of REs recovery from waters. The adsorption–desorption procedure with the optimized parameters was also tested on a leaching solution obtained by dissolution of a dismantled NdFeB magnet of a hard-disk. The clays were fully characterized after REs adsorption and desorption by means of X-ray powder diffraction (XRPD) and X-ray photoelectron spectroscopy (XPS); the liquid phase was characterized via Inductively Coupled Plasma–Optical Emission Spectroscopy (ICP–OES) analyses. The experimental results show that both clays are able to capture and release La and Nd ions, with an ion exchange mechanism. The best total efficiency (capture 50%, release 70%) is obtained when the uptake and release processes are performed at pH = 5 and pH = 1 respectively; in real leached scrap solutions, the uptake is around 40% but release efficiency is strongly decreased passing from a mono-ion system to a real system (from 80% to 5%). Furthermore, a strong matrix effect is found, with the matrix largely affecting both the uptake and the release of neodymium

Clinical Features and Outcome of 79 Dogs With Digital Squamous Cell Carcinoma Undergoing Treatment: A SIONCOV Observational Study

In dogs, digit squamous cell carcinoma (SCC) is uncommon. Clinical signs are frequently underestimated, leading to a diagnostic delay. The purpose of this retrospective study was to report our experience regarding the clinical presentation, diagnostic work-up, treatment and outcome of 79 client-owned dogs with SCC of the digit. The greatest majority (84.8%) of dogs was dark-coated. Schnauzers represented approximately one third of the study population, and had a poorer outcome compared with other breeds. The majority of SCCs occurred in the front limbs (61%), and bone lysis was frequently observed (92.4%). Approximately 9% of dogs had involvement of multiple digits, and this was associated with a shorter time to progression (TTP; P = 0.047). Similarly, a duration of clinical signs >90 days was associated with a shorter TTP (P = 0.02). Regional lymph node metastases were documented in 17.7% of dogs at admission and were significantly associated with tumor-related death (P < 0.001). At presentation, none of the dogs had evidence of distant metastasis. Digit amputation achieved adequate local tumor control in the majority of cases. Adjuvant chemotherapy and radiation therapy were carried out in 21.5% of cases, with uncertain benefit. Due to the relatively non-aggressive clinical behavior of digit SCC, chemotherapy should only be offered in the case of metastatic disease. Approximately one fourth of dogs developed de novo SCCs during the follow-up. Careful examination of the digits should be encouraged in breeds considered at high risk and in dogs with a previous history of digital SCC

Clinical Features and Outcome of 79 Dogs With Digital Squamous Cell Carcinoma Undergoing Treatment: A SIONCOV Observational Study

In dogs, digit squamous cell carcinoma (SCC) is uncommon. Clinical signs are frequently underestimated, leading to a diagnostic delay. The purpose of this retrospective study was to report our experience regarding the clinical presentation, diagnostic work-up, treatment and outcome of 79 client-owned dogs with SCC of the digit. The greatest majority (84.8%) of dogs was dark-coated. Schnauzers represented approximately one third of the study population, and had a poorer outcome compared with other breeds. The majority of SCCs occurred in the front limbs (61%), and bone lysis was frequently observed (92.4%). Approximately 9% of dogs had involvement of multiple digits, and this was associated with a shorter time to progression (TTP; P = 0.047). Similarly, a duration of clinical signs >90 days was associated with a shorter TTP (P = 0.02). Regional lymph node metastases were documented in 17.7% of dogs at admission and were significantly associated with tumor-related death (P < 0.001). At presentation, none of the dogs had evidence of distant metastasis. Digit amputation achieved adequate local tumor control in the majority of cases. Adjuvant chemotherapy and radiation therapy were carried out in 21.5% of cases, with uncertain benefit. Due to the relatively non-aggressive clinical behavior of digit SCC, chemotherapy should only be offered in the case of metastatic disease. Approximately one fourth of dogs developed de novo SCCs during the follow-up. Careful examination of the digits should be encouraged in breeds considered at high risk and in dogs with a previous history of digital SCC

RARE EARTHS RECOVERY BY SOLID-LIQUID EXTRACTION WITH NATURAL AND MODIFIED CLAYS

Nowadays there is an increasing need for Rare Earths (REs) due to their usage in numerous high-technology applications, so their recycling from Waste Electrical and Electronic Equipment (WEEE) can only be considered a valuable opportunity: this perspective is known as “urban mining” [1]. Among others, the use of solid-liquid extraction is obtaining more and more attention because of many advantages such as high recovery, short extraction time, high enrichment factor, low cost and no consumption of organic solvents [2]. The critical step in such a recovery process is the metal ions removal from the aqueous solutions. Recently, clays have been proposed as solid-phase being characterized by low cost, good mechanical properties, good acid tolerance, convenient solid-liquid separation and excellent reusability. Furthermore, clays show a natural adsorption behaviour towards REs [3]. On these bases, the aim of the present work is the study of REs recovery from WEEE via solid- liquid extraction. For this purpose different solid sorbents were considered, namely two natural smectite mineral clays (STx-1 and SWy- 2) and four modified organo-clays. Their effectiveness towards adsorption and release of lanthanum ions (selected as representing element of the REs family) model solutions was tested. Modified clays were synthesized by intercalating two different polymers having chelating properties, N-(methoxy-polyethylene glycol) ethylene diamine and N-(methoxy-polyethylene glycol) ethylene diamine trimethylene phosphonic acid. All the solid materials were characterized by FT-IR, thermo gravimetric analyses (TGA), X-ray diffraction (XRD) and XPS analyses, while the amounts of the intercalated polymer were estimated by COD (Chemical Oxygen Demand) analysis. Also the intercalation mechanism was investigated, varying the operating parameters, such as polymer concentration and pH in order to select the optimal intercalation conditions. The best organo-clay system was produced using 90 mM of initial polymer concentration and an intercalation pH of about 11, corresponding to a not-protonated condition of the chelating amino-groups. The adsorbed and released lanthanum ions were estimated by ICP-OES. A global efficiency (uptake and release) of lanthanum recovery around 30-35% was found for both pristine clays, while an improvement of the efficiency up to 43% was measured upon intercalation. Also the mechanisms and the kinetics of these reactions were evaluated and the results were mainly related to the amount and the nature of the intercalated polymer present in the clay

Mechanochemical transformation of an organic ligand on mineral surfaces: the efficiency of birnessite in catecholdegradation

The aim of this work is to investigate the efficiency of the phyllomanganate birnessite in degrading catechol after mechanochemical treatments. A synthesized birnessite and the organic molecule were grounded together in a high energy mill and the xenobiotic-mineral surface reactions induced by the grinding treatment have been investigated by means of X-ray powder diffraction, X-ray fluorescence, thermal analysis and spectroscopic techniques as well as high-performance liquid chromatography and voltammetric techniques. If compared to the simple contact between the birnessite and the organic molecule, mechanochemical treatments have revealed to be highly efficient in degrading catechol molecules, in terms both of time and extent. Due to the two phenolic groups of catechol and the small steric hindrance of the molecule, the extent of the mechanochemically induced degradation of catechol onto birnessite surfaces is quite high. The degradation mechanism mainly occurs via a redox reaction. It implies the formation of a surface bidentate inner-sphere complex between the phenolic group of the organic molecules and the Mn(IV) from the birnessite structure. Structural changes occur on the MnO6 layers of birnessite as due to the mechanically induced surface reactions: reduction of Mn(IV), consequent formation of Mn(III) and new vacancies, and free Mn2+ ions production.The aim of this work is to investigate the efficiency of the phyllomanganate birnessite in degrading catechol after mechanochemical treatments. A synthesized birnessite and the organic molecule were grounded together in a high energy mill and the xenobiotic-mineral surface reactions induced by the grinding treatment have been investigated by means of X-ray powder diffraction, X-ray fluorescence, thermal analysis and spectroscopic techniques as well as high-performance liquid chromatography and voltammetric techniques.If compared to the simple contact between the birnessite and the organic molecule, mechanochemical treatments have revealed to be highly efficient in degrading catechol molecules, in terms both of time and extent. Due to the two phenolic groups of catechol and the small steric hindrance of the molecule, the extent of the mechanochemically induced degradation of catechol onto birnessite surfaces is quite high. The degradation mechanism mainly occurs via a redox reaction. It implies the formation of a surface bidentate inner-sphere complex between the phenolic group of the organic molecules and the Mn(IV) from the birnessite structure. Structural changes occur on the MnO 6 layers of birnessite as due to the mechanically induced surface reactions: reduction of Mn(IV), consequent formation of Mn(III) and new vacancies, and free Mn 2+ ions production. © 2011 Elsevier B.V.

Use of natural clays as sorbent materials for rare earth ions: Materials characterization and set up of the operative parameters

Two mineral clays of the montmorillonite group were tested as sorbents for the removal of Rare Earths (REs) from liquid solutions. Lanthanum and neodymium model solutions were used to perform uptake tests in order to: (a) verify the clays sorption capability, (b) investigate the sorption mechanisms and (c) optimize the experimental parameters, such as contact time and pH. The desorption was also studied, in order to evaluate the feasibility of REs recovery from waters. The adsorption-desorption procedure with the optimized parameters was also tested on a leaching solution obtained by dissolution of a dismantled NdFeB magnet of a hard-disk. The clays were fully characterized after REs adsorption and desorption by means of X-ray powder diffraction (XRPD) and X-ray photoelectron spectroscopy (XPS); the liquid phase was characterized via Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) analyses. The experimental results show that both clays are able to capture and release La and Nd ions, with an ion exchange mechanism. The best total efficiency (capture ≈ 50%, release ≈ 70%) is obtained when the uptake and release processes are performed at pH = 5 and pH = 1 respectively; in real leached scrap solutions, the uptake is around 40% but release efficiency is strongly decreased passing from a mono-ion system to a real system (from 80% to 5%). Furthermore, a strong matrix effect is found, with the matrix largely affecting both the uptake and the release of neodymium

Lanthanum captured in montmorillonite: Evidence of inner-sphere complexes from X-ray Absorption Spectroscopy investigations

An X-Ray Absorption Spectroscopy (XAS) study of the local structural environment of La ions hosted in mont-morillonite is presented. The structural location of La ions in the host phases and whether they are incorporated in the structure or adsorbed at the surface has been assessed. Two clays from the Clay Mineral Society repository (STx and SWy) in pristine form and polymer-modified with penta-ethylen-hexamine (C10H28N6) have been studied. Ca and Na-rich montmorillonite have been contacted with 19 and 200 mM La solutions. XAS results yielded La-O distances ranging between 2.57 and 2.61 & Aring;, compatible with literature data for La ions coordi-nated by water molecules. We provide evidence for the presence of a further La-Si/Al distance suggesting that La may also be bonded to the oxygen atoms on the outer surfaces of the TOT layer. Such a feature may play an important role in limiting the release/efficiency of the process. This paper is a further step in the research for REEs recovery from Electric and Electronic wastes (WEE) via a solid-liquid process, and their re-use as secondary raw materials. The knowledge of the ions-sorbent interaction mechanism, such as its nature and strength, is a fundamental information to tailor sorbents and procedures in practical applications

Adjuvant anthracycline-based vs metronomic chemotherapy vs no medical treatment for dogs with metastatic splenic hemangiosarcoma: A multi-institutional retrospective study of the Italian Society of Veterinary Oncology

Treatment options for dogs with metastatic (stage III) splenic hemangiosarcoma are limited. A doxorubicin-based chemotherapy regimen is commonly administered; however, there are no published data to support this practice. The aim of this study was to investigate the impact of maximum-tolerated-dose chemotherapy (MTD), metronomic chemotherapy (MC) and no adjuvant treatment on outcome in dogs with stage III splenic hemangiosarcoma undergoing splenectomy. Medical records of dogs with stage III splenic hemangiosarcoma that underwent splenectomy followed by MTD chemotherapy, MC or no adjuvant treatment were retrieved. Time to progression (TTP), survival time (ST) and toxicity were evaluated. One hundred three dogs were identified: 23 received adjuvant MTD, 38 MC and 42 were not medically treated. Overall median TTP and ST were 50 (95% confidence interval [CI], 39-61) and 55 days (95% CI, 43-66), respectively. Dogs treated with adjuvant MTD had a significantly longer TTP and ST compared with dogs receiving MC (median TTP, 134 vs 52 days, P = .025; median ST, 140 vs 58 days, P = .023, respectively). Dogs treated by splenectomy only had the shortest median TTP (28 days) and ST (40 days). However, treatment-related adverse events (AEs) were significantly more frequent in the MTD group (P = .017). The outcome for dogs with metastatic splenic hemangiosarcoma is poor. While MTD showed greater efficacy compared to MC, toxicity was higher in this group. Treatment-related AEs need to be carefully balanced against this modest survival prolongation when offering adjuvant MTD to dogs with advanced stage hemangiosarcoma

Cannabis/Hemp for Sustainable Agriculture and Materials

International audienceTreatment of wastewater pollution is a critical issue in the context of growing population and industrialization. Actual treatment methods are expensive and not fully effective and rely on fossil fuel-derived chemicals, thus calling for alternative adsorption methods on natural materials such as hemp. Industrial hemp (Cannabis sativa Linn) is a high-yielding annual industrial crop harvested for its fiber from the stem and its oil from the seeds. Hemp is a multi-purpose plant with great potential because of its many uses, such as building materials, textiles, paper, food and beverage, automotive, cosmetics, and medicine. Wastewater treatment is another innovative application. Indeed, the past decade has shown an explosion in the study of hemp-based materials for the biosorption of metal ions from effluents, demonstrating that industrial hemp is one of the most promising materials for environmental applications. Hemp products can be used as biosorbents in granular or felt forms or to prepare non-conventional activated carbons, both used in biosorption-oriented processes. In this chapter, after a brief description of biosorption, the use of different types of hemp-based materials that can be used as pollutant biosorbents is described.&nbsp

Hemp-Based Materials for Applications in Wastewater Treatment by Biosorption-Oriented Processes: A Review

Treatment of wastewater pollution is a critical issue in the context of growing population and industrialization. Actual treatment methods are expensive and not fully effective and rely on fossil fuel-derived chemicals, thus calling for alternative adsorption methods on natural materials such as hemp. Industrial hemp (Cannabis sativa Linn) is a high-yielding annual industrial crop harvested for its fiber from the stem and its oil from the seeds. Hemp is a multi-purpose plant with great potential because of its many uses, such as building materials, textiles, paper, food and beverage, automotive, cosmetics, and medicine. Wastewater treatment is another innovative application. Indeed, the past decade has shown an explosion in the study of hemp-based materials for the biosorption of metal ions from effluents, demonstrating that industrial hemp is one of the most promising materials for environmental applications. Hemp products can be used as biosorbents in granular or felt forms or to prepare non-conventional activated carbons, both used in biosorption-oriented processes. In this chapter, after a brief description of biosorption, the use of different types of hemp-based materials that can be used as pollutant biosorbents is described