Chitosan Beads as Eco-Friendly Biosorbent for the Biosorption of Au(III) and Cu(II) from Aqueous Solutions

This work aimed to study the biosorption of metal ions by chitosan beads, conducted at room temperature by adding chitosan beads into a conical flask containing different initial pH. The flask was agitated, and the concentrations of metal ions were determined using inductively coupled plasma-optical emission spectrometry (ICP-OES). It was found that the sorption percentage and capacity on the effect of pH for metal ions increased with pH and hit a plateau at pH 3 for single-metal solutions, while binary-metal solutions hit a plateau at pH 2. A consideration separation of Au(III) from Cu(II) could also be achieved at pH 3-5. Keywords: biosorption; chitosan beads; Au(III); Cu(II) eISSN: 2398-4287 © 2022. The Authors. Published for AMER ABRA cE-Bs by e-International Publishing House, Ltd., UK. This is an open-access article under the CC-BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer–review under the responsibility of AMER (Association of Malaysian Environment-Behaviour Researchers), ABRA (Association of Behavioural Researchers on Asians/Africans/Arabians), and cE-Bs (Centre for Environment-Behaviour Studies), Faculty of Architecture, Planning & Surveying, Universiti Teknologi MARA, Malaysia. DOI: https://doi.org/10.21834/ebpj.v7i21.366

Processing of Waste Copper Converter Slag Using Organic Acids for Extraction of Copper, Nickel, and Cobalt

An innovative, economical, and environmentally sound hydrometallurgical process has been proposed for recovering Cu, Ni, and Co from copper-rich converter slag by organic acids. In the leaching experiments, the eects of organic acid concentrations, pulp density,temperature, and time were investigated. Optimum recovery of 99.1% Cu, 89.2% Ni, 94% Co, and 99.2% Fe was achieved in 9–10 h at 308 K (35 oC) temperature and 15% pulp density with 2 N citric acid using <45 micron particles. Pourbaix diagrams of metal-water-citrate systems were supplemented to examine solubility of ligands at the desired conditions. Furthermore, the leaching mechanism was based on the SEM-EDS (energy-dispersive X-ray spectroscopy) and XRD characterization as well as the leaching results obtained

Analisi scientifiche sulle tempere murali di Villa Pace

International audienceThe morphology, mineralogy, and solid-liquid phase separation of the Cu and Zn precipitates formed with sulfide produced in a sulfate-reducing bioreactor were studied at pH 3, 5, and 7. The precipitates formed at pH 7 display faster settling rates, better dewaterability, and higher concentrations of settleable solids as compared to the precipitates formed at pH 3 and 5. These differences were linked to the agglomeration of the sulfidic precipitates and coprecipitation of the phosphate added to the bioreactor influent. The Cu and Zn quenched the intensity of the dissolved organic matter peaks identified by fluorescence-excitation emission matrix spectroscopy, suggesting a binding mechanism that decreases supersaturation, especially at pH 5. X-ray absorption fine structure spectroscopy analyses confirmed the precipitation of Zn-S as sphalerite and Cu-S as covellite in all samples, but also revealed the presence of Zn sorbed on hydroxyapatite. These analyses further showed that CuS structures remained amorphous regardless of the pH, whereas the ZnS structure was more organized at pH 5 as compared to the ZnS formed at pH 3 and 7, in agreement with the cubic sphalerite-type structures observed through scanning electron microscopy at pH 5

Role of Biochar in Anaerobic Digestion Based Biorefinery for Food Waste

The effect of biochar addition on the anaerobic digestion (AD) of food waste was evaluated. From the five biochars tested, Fe, Co, Ni, and Mn were leached in very small quantities (&lt;10 mg/kg), while a high amount of K (1,510 and 1,969 mg/kg) was leached from treated waste wood and willow tree pyrochar, respectively. AD batch experiments were performed at an inoculum:substrate ratio of 1:1, at 30°C and under agitating conditions. The results showed that the biogas volume produced by the treatments with the brewery residue hydrochar and treated waste wood pyrochar was lower than the amount of biogas produced by the control with only food waste. The food waste supplemented with 1.5 mL of trace elements yielded the highest biogas of 588 mL/g COD (CH4 content−48%). Furthermore, two identical upflow anaerobic sludge blanket (UASB) reactors, i.e., control reactor and biochar amended reactor, were operated at 30°C, at organic loading rates (OLR) varying from 3.4 to 7.8 g COD/L.day. The average COD removal efficiencies of the control and the biochar-amended reactor were 47 and 77% at an OLR of 6.9–7.8 g COD/L.day, respectively. These study results clearly indicate that the type of biochar and trace elements concentration in biochar play a key role in determining the effectiveness of the biochar in enhancing biogas production from food waste

Analysis, design and "in silico" evaluation of e-selectin antagonists

E-selectin, is member of a family of cell-adhesion proteins, which plays a crucial role in many physiological processes and diseases [1], and in particular, in the early phases of the inflammatory response. Its role is to promote the tethering and the rolling of leukocytes along the endothelial surface [2]. These steps are then followed by integrin-mediated firm adhesion and final transendothelial migration. Therefore, control of the leukocyte-endothelial cell adhesion process may be useful in cases, where excessive recruitment of leukocytes can contribute to acute or chronic diseases such as stroke, reperfusion injury, psoriasis or rheumatoid arthritis [3]. In this work, efforts to develop in silico-based protocols to study the interaction between E-selectin and its ligands, are presented. Hence, different protocols had to be developed and validated. In particular, a new procedure for the analysis of the conformational preferences of E-selectin antagonists was established and the results compared to those obtained with the MC(JBW)/SD approach, which had already demonstrated its validity in the past [161,168]. Thus, the comparison between the two protocols permitted to recognize a different conformational preference of the two methods for the orientation of the sialic acid moiety of sLex (3) (torsions Φ3 and Ψ3, Figure A), which reflects the contrasting opinions existing for the conformation adopted by sLex (3) in solution [150–168]. A more detailed analysis revealed that probably both approaches deliver only a partially correct view and that in reality, in solution, sLex (3) exists as a mixture of low energy conformers and not as supposed to date [150–154,161–163] as a population of a single conformer. In addition, a docking routine was established and the impact of different partialcharge methods and of explicit solvation on the binding mode studied. MD simulations enabled to gain an insight into the dynamical character of the protein-ligand interactions. In particular, the observations done in an atomic-force microscopy study [350], describing the interactions between the carboxylic group of sLex and Arg97, and between the 3– and 4–hydroxyls of fucose and the calcium ion, as the two main energy barriers for the dissociation process of the protein-ligand complex, found confirmation in our MD-investigations. Thus, these two contacts always lasted longer than any other in the MD simulation. QSAR-models with Quasar [270–272,351] and Raptor [315,316,335] were successfully derived and will permit a semi-quantitative in silico estimation of the binding affinity for the ligands that will be designed in the future. Finally, the developed protocols and models were applied for the development of new E-selectin antagonists. Unfortunately, to date, only few biological data is available to evaluate our design strategies. However, the impact of the ligand’s pre-organization on the binding affinity could be established at least for the Lexcore of sLex (3). Hence, the importance of the exo-anomeric effect, of the steric compression, and of the hydrophobic interaction between the methyl group of fucose and the β-face of galactose was clearly demonstrated

A review of nature-based solutions for urban water management in European circular cities: a critical assessment based on case studies and literature

Abstract Nature-based solutions (NBS) can protect, manage and restore natural or modified ecosystems. They are a multidisciplinary, integrated approach to address societal challenges and some natural hazards effectively and adaptively, simultaneously providing human well-being and biodiversity benefits. NBS applications can be easily noticed in circular cities, establishing an urban system that is regenerative and accessible. This paper aims to offer a review on NBS for urban water management from the literature and some relevant projects running within the COST Action 'Implementing nature-based solutions for creating a resourceful circular city'. The method used in the study is based on a detailed tracking of specific keywords in the literature using Google Scholar, ResearchGate, Academia.edu, ScienceDirect and Scopus. Based on this review, three main applications were identified: (i) flood and drought protection; (ii) the water-food-energy nexus; and (iii) water purification. The paper shows that NBS provide additional benefits, such as improving water quality, increasing biodiversity, obtaining social co-benefits, improving urban microclimate, and the reduction of energy consumption by improving indoor climate. The paper concludes that a systemic change to NBS should be given a higher priority and be preferred over conventional water infrastructure

Towards a Cross-Sectoral View of Nature-Based Solutions for Enabling Circular Cities

A framework developed by the COST Action Circular City (an EU-funded network of 500+ scientists from 40+ countries; COST = Cooperation in Science and Technology) for addressing Urban Circularity Challenges (UCCs) with nature-based solutions (NBSs) was analyzed by various urban sectors which refer to different fields of activities for circular management of resources in cities (i.e., reducing use of resources and production of waste). The urban sectors comprise the built environment, urban water management, resource recovery, and urban farming. We present main findings from sector analyses, discuss different sector perspectives, and show ways to overcome these differences. The results reveal the potential of NBSs to address multiple sectors, as well as multiple UCCs. While water has been identified as a key element when using NBSs in the urban environment, most NBSs are interconnected and also present secondary benefits for other resources. Using representative examples, we discuss how a holistic and systemic approach could facilitate the circular use of resources in cities. Currently, there is often a disciplinary focus on one resource when applying NBSs. The full potential of NBSs to address multifunctionality is, thus, usually not fully accounted for. On the basis of our results, we conclude that experts from various disciplines can engage in a cross-sectoral exchange and identify the full potential of NBSs to recover resources in circular cities and provide secondary benefits to improve the livelihood for locals. This is an important first step toward the full multifunctionality potential enabling of NBSs