Removal of Arsenic (III) from water with a combination of Graphene Oxide (GO) and Granular Ferric Hydroxide (GFH) at the optimum molecular ratio

The occurrence of arsenic in water is a global problem for public health. Several removal technologies have been developed for arsenic removal from water, and adsorption onto iron oxyhydroxides is the most widely used technique. Granular ferric hydroxide (GFH) has been used mainly for As(V) removal, but it has the disadvantage that it can create a problem with the residual concentration of iron in the water. Moreover, graphene oxide (GO), which contains a large amount of reactive oxygen, exhibits high adsorbing capacity. In this study, the combined use of GO and GFH as adsorbent materials in different molar ratios was investigated in order to achieve the maximum As(III) removal from aqueous solutions. The effect of the adsorbent’s dosage, pH value, contact time, initial As(III), and different molar ratios of GO/GFH was examined. As depicted, the presence of GFH enhances the use of GO. In particular, the molar ratio of GO/GFH 2:1 (i.e., 0.2 g/L GO and 0.1 g/L GFH) is chosen as optimal at pH value 7.0 ± 0.1, while the removal percentage increased from 10% (absence of GFH) to 90% with the simultaneous addition of GFH. Freundlich isotherm and pseudo-second-order kinetic models described the experimental data adequately and the highest adsorption capacity that was achieved was 22.62 µg/g

Role of EU and non-EU universities in achieving environmental sustainability

At present, the principles of sustainable development are being implemented in almost all economy sectors whereas one of the key drivers of the transition to a new concept is higher education system also. The inclusion of special academic disciplines on sustainable development, the implementation of environmental protection measures, financial support for research in the field of environmental sciences, campuses landscape – all these stimulates the process of transition to a concept of sustainable development. In addition, higher education makes it possible to form an ecological worldview among the younger generation that is an effective tool in achieving sustainable development goals (SDGs). University graduates who understand the need to achieve the SDGs and provide environmental protection, lead an eco-friendlier lifestyle and pass on the knowledge they have gained to their children or other family members. The purpose of this study is to analyze the relationship between the involved activity of universities in the field of sustainable development and the implementation of large-scale government programs to achieve environmental sustainability. The study will examine the experience of Eu and non-EU universities and state environmental protection programs. The results obtained allow us to conclude about the correlation between educational activities in the higher education system and achievements at the state level of environmental sustainability

A mini review of recent findings in Cellulose-, Polymer- and Graphene-based membranes for Fluoride removal from drinking water

Effective fluoride removal from water is a persistent global concern both for drinking water and wastewater treatment. According to World Health Organization (WHO) standards the maximum contaminant level in drinking water cannot be higher than 1.5 mg F 12 L-1 since affects the skeletal and nervous systems of humans. Various technologies have been developed to decrease fluoride concentration from waters, such as adsorption, coagulation, precipitation and membrane separa-tion. Membrane technology found to be a very effective technology, significantly reducing fluo-ride to desired standards levels; however, has received less attention than other technologies because it is apparent as a costly process. This review aims to discuss the recent studies using modified membranes for fluoride removal. Emphasis is given on cellulose, polymer and gra-phene based membranes and is further discussing the modification of membranes with several metals that have been developed in the last years. It was observed that the main focus of the to-tal publications, has been on the use of polymer based membranes. Most of the membranes ap-plied for defluoridation exhibit greater efficiency at pH values close to that of drinking water (i.e., 6\u20138).and maximum treatment capacity was obtained with the use of a cellulose modified membrane Fe-Al-Mn@chitosan with a permeate flux of 2000 L m-2 h-1, following the carbon based amyloid fibril nano-ZrO2 composites (CAF-Zr) 1750 L m-2. A technical-economic comparison study of NF and RO is also referred, concluding that NF membrane is slightly less expensive

A Mini Review of Recent Findings in Cellulose-, Polymer- and Graphene-Based Membranes for Fluoride Removal from Drinking Water

Effective fluoride removal from water is a persistent global concern both for drinking water and wastewater treatment. According to World Health Organization (WHO), standards for the maximum contaminant level in drinking water cannot be higher than 1.5 mg F− L−1 since affects the skeletal and nervous systems of humans. Various technologies have been developed to decrease fluoride concentration from waters, such as adsorption, coagulation, precipitation and membrane separation. Membrane technology has been found to be a very effective technology, significantly reducing fluoride to desired standards levels; however, it has received less attention than other technologies because it is a costly process. This review aims to discuss the recent studies using modified membranes for fluoride removal. Emphasis is given on cellulose-, polymer- and graphene-based membranes and is further discussing the modification of membranes with several metals that have been developed in the last years. It was observed that the main focus of the total publications has been on the use of polymer-based membranes. Most of the membranes applied for defluoridation exhibit greater efficiency at pH values close to that of drinking water (i.e., 6–8), and maximum treatment capacity was obtained with the use of a cellulose modified membrane Fe-Al-Mn@chitosan with a permeate flux of 2000 L m−2 h−1, following the carbon-based amyloid fibril nano-ZrO2 composites (CAF-Zr) 1750 L m−2. A technical-economic comparison study of NF and RO is also referred, concluding that NF membrane is slightly less expensive

Synthesis and characterization of novel pre-polymerized inorganic coagulants and their application in water and wastewater treatment

The aim of the present thesis was to synthesize and characterize novel pre-polymerized inorganic coagulants and to evaluate their efficiency in water and wastewater treatment applications. More than 40 new types of composite pre-polymerized coagulants were prepared by combining iron, aluminum and polysilic acid (pSi) or polyelectrolyte (PE) salts. Initially, the new composite inorganic coagulants were characterized and examined in the treatment of simulated surface water. Subsequently, tests were conducted for the treatment of simulated groundwater, in order to remove various undesirable components present in it, such as fluoride. Selected coagulants were also studied for their efficacy in treating real wastewater samples. Based on the results, it is recommended that a coagulant of poly-aluminum-ferric-silicate-chloride type, with improved properties, should have a medium basicity, relatively low silicon and iron content, and should preferably be prepared by the co-polymerization technique.Σκοπός της διατριβής ήταν η σύνθεση και ο χαρακτηρισμός νέων βελτιωμένων προ-πολυμερισμένων ανόργανων κροκιδωτικών υλικών και η αξιολόγηση της εφαρμογής αυτών στην επεξεργασία νερού και υγρών αποβλήτων. Παρασκευάστηκαν περισσότερα από 40 νέου τύπου σύνθετα προ-πολυμερισμένα αντιδραστήρια κροκίδωσης με συνδυασμό αλάτων σιδήρου, αργιλίου και πολυπυριτικού οξέως (pSi) ή πολυηλεκτρολύτη (PE). Αρχικά, χαρακτηρίστηκαν και δοκιμάστηκαν τα νέα σύνθετα ανόργανα κροκιδωτικά αντιδραστήρια, στην κατεργασία του προσομοιωμένου επιφανειακού νερού. Στη συνέχεια, έγιναν δοκιμές για την επεξεργασία προσομοιωμένων υπόγειων νερών, με σκοπό την απομάκρυνση διάφορων ανεπιθύμητων συστατικών που υπάρχουν σε αυτό, όπως είναι το φθόριο. Επιλεγμένα κροκιδωτικά υλικά μελετήθηκαν επίσης, ως προς την αποτελεσματικότητά τους στην κατεργασία πραγματικών δειγμάτων υγρών αποβλήτων. Βάσει των αποτελεσμάτων, συνιστάται ότι ένα κροκιδωτικό υλικό του τύπου poly-aluminum-ferric-silicate-chloride, με βελτιωμένες ιδιότητες θα πρέπει να έχει μέση βασικότητα, σχετικά χαμηλή περιεκτικότητα πυριτίου και σιδήρου, και θα πρέπει να παρασκευάζεται κατά προτίμηση με την τεχνική του συμπολυμερισμού

Graphene Oxide/Fe-Based Composite Pre-Polymerized Coagulants: Synthesis, Characterization, and Potential Application in Water Treatment

This study presents for the first time the synthesis and characterization of GO (graphene oxide), PFSiC (polyferric silicate chloride), and hybrid GO-PFSiC derivatives, aiming to enhance synergistically the performance of coagulation, when applied for the treatment of water. The structure and the morphology of composite GO-PFSiC coagulants were studied in detail by the application of FTIR, XRD, and SEM characterization techniques. Furthermore, the proposed coagulants were applied for the treatment of simulated turbid surface water. The effects of the reagent’s dosage, pH value, and experimental/operational conditions on the coagulation efficiency, applied mainly for the removal of turbidity, were examined. The results, obtained from the FTIR and XRD measurements, showed the presence of a bond between the PFSiC and the GO surface, indicating that the PFSiC particles are distributed uniformly on the surface of graphene, which was also confirmed by the SEM images. Especially, the composite compound GO-PFSiC1.5-15-0.5 presents the most uniform distribution of iron on the surface of graphene oxide and exhibits the optimum coagulation efficiency, while it significantly reduces the turbidity for doses above 3–5 mg/L, i.e., achieving the respective legislation limit as proposed by WHO. Specifically, at the alkaline pH values (>7.9), the removal of turbidity reaches 96%. Consequently, the results of this study render these materials as potential coagulant agents for further research and applications, aiming to also achieve the co-removal of other water components

Second-hand smoke exposure effects on human health: Evaluation of PM10 concentrations in the external areas of a university campus

Studies about the measurement of outdoor tobacco smoke (OTS) are limited to a few very recent studies. In many countries around the world, within public buildings, smoking is prohibited by law. However, these prohibitions often drive smokers to move to the border of the areas where smoking is forbidden, typically the entrances of buildings, in order to smoke. When many smokers stand outdoors near the entrances, a significant \u201cwall\u201d of smoke is generated. This condition exposes nonsmokers to smoke and contaminates the indoor environment too. Such a situation is amplified if the outdoor external area is covered. This paper presents a work carried out in a university campus, near building entrances, with the aim of studying the second-hand smoke (SHS) exposure in outdoor conditions. Measurements of particulate matter in specific environmental conditions are evaluated to estimate the OTS impacts on the students and the academic staff. The results showed that the exposure to tobacco can be very high and even comparable to values found when tests were carried out indoors, at the same distances from the smokers. A discussion about forbidding smoking near the entrances of public buildings is reported, including considerations about the environmental and public health concerns induced by SHS exposure and the smoking activity

Role of EU and non-EU universities in achieving environmental sustainability

At present, the principles of sustainable development are being implemented in almost all economy sectors whereas one of the key drivers of the transition to a new concept is higher education system also. The inclusion of special academic disciplines on sustainable development, the implementation of environmental protection measures, financial support for research in the field of environmental sciences, campuses landscape – all these stimulates the process of transition to a concept of sustainable development. In addition, higher education makes it possible to form an ecological worldview among the younger generation that is an effective tool in achieving sustainable development goals (SDGs). University graduates who understand the need to achieve the SDGs and provide environmental protection, lead an eco-friendlier lifestyle and pass on the knowledge they have gained to their children or other family members. The purpose of this study is to analyze the relationship between the involved activity of universities in the field of sustainable development and the implementation of large-scale government programs to achieve environmental sustainability. The study will examine the experience of Eu and non-EU universities and state environmental protection programs. The results obtained allow us to conclude about the correlation between educational activities in the higher education system and achievements at the state level of environmental sustainability

Removal of Arsenic, Chromium and Uranium from Water Sources by Novel Nanostructured Materials Including Graphene-Based Modified Adsorbents: A Mini Review of Recent Developments

Groundwater is commonly used as a drinking water resource all over the world. Therefore, groundwater contamination by toxic metals is an important issue of utmost concern for public health, and several technologies are applied for their effective removal, such as coagulation, ion exchange, adsorption, and membrane applications like reverse osmosis. Adsorption is acknowledged as a simple, effective and economic technology, which has received increased interest recently, despite certain limitations regarding operational applications. The respective scientific efforts have been specifically focused on the development and implementation of novel nano-structured adsorbent materials, which may offer extensive specific surface areas, much higher than the conventional adsorbents, and hence, are expected to present higher removal efficiencies of pollutants. In this paper, the recent developments of nanomaterial applications for arsenic, chromium and uranium removal from groundwaters are critically reviewed. Particularly, the use of novel composite materials, based mainly on hybrid metallic oxide nanoparticles and on composites based on graphene oxide (GO) (i.e., graphene-based hybrids), showed promising evidences to achieve efficient removal of toxic metals from water sources, even in full scale applications