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Porous anorthite (CaAl2Si2O8) ceramics, suitable for thermal insulation in buildings, were obtained using waste seashells as a source of CaO, kaolin as a source of Al2O3 and SiO2 and banana peel as a pore former. Changing the volume of banana peel as well as the processing temperature was found to be an effective approach to control the thermo-mechanical properties of the obtained anorthite ceramics. The sintering of powder compacts containing up to 30 wt% banana peel at temperatures ranging from 1100 to 1200 °C resulted in anorthite ceramics possessing up to 45% open porosity, a compressive strength between 13 and 92 MPa, a bulk density between 1.87 and 2.62 g/cm3 and thermal conductivity between 0.097 and 3.5 W/mK. It was shown that waste materials such as seashells and banana peel can be used to obtain cost-effective thermal insulation in buildings.

Technetium-99 (99Tc), as one of the important high-yield fission products, is a significant threat to the environment and human health. It is produced in large amounts by nuclear fission of 235U or 239Pu in nuclear reactions, though the quantity of Tc produced by the spontaneous fission of 238U or by decay of 99Mo in the nature which is very small. 99Tc in the environment originates from nuclear weapons tests, discharges from nuclear power plants, nuclear medicine and radiobiology. These activities generate large volumes of low and intermediate radioactive waste which can cause a significant impact on the environment if disposed without suitable treatment. Immobilization of 99Tc into a relatively small volume waste is vital for long term permanent disposal. High mobility and long half-life of 99Tc considered to be one of the most important radionuclides in safety assessment of environmental radioactivity as well as nuclear waste management. Effective removal of radioactive technetium (99Tc) from contaminated water is of enormous importance from an environmental and public health perspective, yet many current methodologies are highly ineffective. This paper summarizes physico-chemical separation procedures emphasizing those that are the most used in practice. Classic sorbents such as activated carbons, ion exchange resins as well, as new materials, such as metal−organic frameworks and graphene based membranes are described in the paper.

Seashells piled in coastal areas worldwide, particularly near commercial mollusk farms, may pose a substantial environmental and health risk. Utilizing seashell waste (SW) as a natural liming material represents a meaningful contribution to the sustainable development of the aquaculture industry through resource recovery. This study assessed the effects of adding various doses of finely ground SW to acidic agricultural soil with elevated total concentration of Cu (219.2 mg/kg) on the bioavailability of selected metals (Cu, Zn, Fe, Mn, Co, Pb, Ni, and Cd). The concentration of DTPA-extracted forms of Cu and other elements decreased significantly with the increase in SW dose from 0.15% to 2%, whereas differences between 2% and 5% treatments were not significant. The association of metals' bioavailability with the agrochemical properties of control and treated soil samples revealed the leading influence of soil pH. Furthermore, the DTPA-extracted amounts of Cu and Zn were negatively correlated with carbonate and organic carbon content, and bioavailable Zn forms were negatively correlated with the content of accessible phosphorus. As a cost-effective, sustainable, and renewable source of calcium carbonate, organic carbon, and available phosphorus, SW is a candidate material for acidic soil amelioration, including the immobilization of a range of toxic and potentially toxic metals. However, the study's results underline that SW dose optimization through preliminary tests is a necessary research component that requires observing soil fertility parameters, particularly the status of essential metals.

Pollution of the environment is a serious issue nowadays, and finding a proper wastewater treatment is only small part of challenges that humans are facing. In order to find innovative ways for wastewater treatment, different techniques are applied, which lead to the production of new materials, such as ones made of polymeric nanofibers and materials with photocatalytic properties. In this study, nanofibers composite, synthetized from polyamide (PA) and UiO-66 Metal Organic Framework (MOF) by electrospinning method was used for degradation of Congo red dye from 10 ppm aqueous solution in batch conditions. Ultra-thin PA nanofiber membranes were produced with different ratios of MOF - 0.5 wt.%, 1 wt.%, 2 wt.% and 10 wt.% and prior the experiments, in order to be easily applied and removed from the solution, cut in the rectangular shape 1cm x 2 cm. FTIR, XRD and SEM are used for characterization of selected composites, prior and after sorption and photocatalytic experiments, while for determination of dye concentration UV-ViS spectrophotometer was used. The best performance in Congo red degradation was shown by membranes which contained 1 wt.% of MOF. FTIR spectra have shown that, upon the introduction of MOF particles into the PA fiber, reduction of all the peaks by the same amount in intensity indicates no interaction between MOF additive and PA matrix. Further, a new peak appeared after sorption at 590 cm-1 and disappeared after dye degradation induced by sun irradiation. XRD analysis has shown that there are no observable microstructural changes in composites upon sorption and cycling. Decreasing of the band gap of composite compared to pure MOF indicated increased photocatalytic activity. Reusability of composite membranes was investigated by performing experiments in multiple cycles, and results have shown that electrospun UiO-66/polyamide membranes have no significant changes in degradation efficiency of Congo red upon 4 cycles.

Worldwide water bodies have been affected by toxic effluents of industries, such as organic compounds, and are continuously deteriorating the environment as industrialization coupled with urbanization has caused the excess release of wastewater. Finding a proper wastewater treatment is of the greatest importance. Gamma irradiation technique, as one of the advanced oxidation techniques, has been widely investigated as a technique for degradation of organic molecules. It has been shown that this method has the potential to be effectively applied for degradation of toxic colorants which show high persistence to degradation. Although the literature abounds with degradation studies of different organic molecules using a wide range of irradiation dozes and doze rates, according to available data, no such irradiation facility exists, mostly due to high doses and expensive equipment needed to be installed. A mechanism of degradation was proposed: generated reactive species non-specifically react with organic compounds leading to their partial or complete degradation. In recent advances, gamma irradiation was coupled with other wastewater treatment technologies to reduce needed doses. Coupling of gamma irradiation was achieved with addition of oxidants which resulted in increased number of reactive species, then coupling with solid matrices, biological treatment, which all lead to additional destabilization of organic molecules. This way, combining different methods of wastewater purification opens new possibilities and may enable the design of a new modular, or even mobile, plant that will satisfy all the needs for its wide commercial application. As a result, a sustainable development goal can be more easily reachable, i.e., sustainable water resources management in future industrial zones and smart cities may be possible without generation of waste transfer into another media.

The main aim of this research is to show influence of different hydroxides, applied in carbon materials activation process on the electrochemical properties of activated carbon samples. The carbon material samples were prepared by hydrothermal treatment of sucrose and thermally activated using KOH, NaOH and LiOH by chemical activation method. The electrochemical properties of the obtained carbon material samples were examined by cyclic voltammetry and electrochemical impedance spectroscopy and correlated to their physicochemical properties. Investigated samples showed characteristic capacitor-like behavior. The best result of specific capacitance was obtained for the sample synthesized treated by KOH, while the increase in capacitance follows the arrangement of the growth of ionic radius of a metal from an alkali which is used for activation. Dependence on the type of hydroxide is due to differences in the radii of a metal. The alkalis with larger radii of metal produce wider pores and consequently the structure of a porous layer become more accessible and available to the charge transfer of capacitive response.

The influence of unconventional alkaline additives (ground seashells and bauxite residue) on the copper (Cu) sorption and retention capacity of acidic soil was investigated. The soil collected near the mining and metallurgical complex in Bor (Serbia) was treated with different doses of additives, and the Cu sorption and desorption were assessed in batch conditions. The waste-derived materials proved to be efficient and sustainable alternatives to conventional alkalizers, increasing the maximum sorption capacity for Cu in correspondence with the soil pH increase. Nevertheless, added Cu was largely mobilized by weak acid extraction, demonstrating the importance of maintaining optimal soil pH for Cu leaching prevention.

Rapid industrialization and increasing population have increased the water demand. Various wastes from industries and anthropogenic activities are discharged into aquatic bodies such as lakes, ponds, rivers, oceans. Therefore, focus is placed on the removal of the contamination from the wastewater. Organic pollutants gained extensive attention because of their toxicity, persistence and significant impacts on human health Among them, organic dyes are complex molecules and most of them are water-soluble, resistant to detergents and heat, exhibit poor biodegradability, etc. Azo dyes are used in about 70% of commercial dyes today, from textile and plastic to cosmetics and food. In this work, removal of azo-type dye Congo Red (CR) from water was performed by using UiO-66 type MOF (Metal Organic Framework), activated carbon (AC) and their composite powder mixture (MOF/AC = 50/50 wt.%). Samples were exposed to solar light irradiation for 1h and 2.5 h, respectively, centrifuged to remove solid particles, and solutions were analyzed by UV-ViS spectrophotometer in order to determine the concentration of the remaining dye. Process was repeated three times in order to explore the renewability of the photocatalysts used, with catalysts dried at 50 °C between cycles. Results revieled superior photocatalytic cycling performance of the MOF compared to the MOF/AC composite, while AC showed decline in dye removal performance due to the saturation of available adsorption sites. MOF/AC composite exhibited beneficial cost/performance ratio.

Mining, combustion of coal and waste, and steel processing are the main industrial activities that trigger the emission of large amounts of Zn, which reach the soil and pose a risk to its services, functions, and groundwater quality. A frequently associated process is soil acidification, reducing soil's ability to retain incoming toxic metals. The soil treatments with reactive, low-cost, and locally available materials might be a straightforward approach to decreasing the mobility of toxic metals and alleviating the environmental risks. This study aimed to compare Zn ions sorption and retention by several unconventional soil additives (seashell waste, bone char, and red mud) against the performance of acidic soil. Batch experiments of Zn ions sorption were initially performed using solutions with different Zn concentrations, followed by the determination of sorbed Zn stability in an acidic medium. The waste materials exhibited higher pH values and superior Zn sorption capacities with respect to the soil. The desorption experiment exposed different mechanisms of Zn ions fixation by studied materials. While the substantial amounts of Zn sorbed by seashells, red mud, as well as soil were released in the scope of the ion exchange and carbonate fraction, sensitive to pH decrease, the bone char preserved Zn in more stable fractions. The investigated waste materials can potentially prevent Zn leaching through the soil profile, with the bone char demonstrating the most significant capability for long-term retention performance.

Most heavy metals, such as Cr (chromium), Pb (lead), Cd (cadmium), Ni (nickel), Cu (copper) and Fe (iron), are extremely toxic above a tolerance limit. These heavy metals in wastewater are not biodegradable and can cause serious harm to human health and ecological environments.1 One of the top-priority toxic heavy metal in wastewater is chromium.2 In natural waters, chromium exists in both trivalent Cr(III) and hexavalent Cr(VI) forms. Cr(VI) is the most toxic one and have the tolerance limit 0.1 mg/L into surface water and 0.05 mg/L in potable water.3 Various methods, such as ion exchange, sedimentation, electrochemical process, cementation, coagulation, adsorption and solvent extraction have been developed for the removal of Cr(VI) and other toxic metals from wastewater.4 Among these methods, in some papers,5-8 adsorption has been used as one of the most effective method for the removal of Cr(VI) from aqueous solutions. Characteristics of adsorption, such as low cost, easy to perform, efficient and reversible method with high operating speed, make this method as most commonly used for the removal of Cr(VI) from aqueous solutions.9 Several adsorbents, like activated alumina,10 zeolites,11 natural bisorbents such as chitosan,12 but also activated carbon13 have been used for the removal of Cr(VI) from aqueous solutions. Due to the high cost, commercial activated carbon is not available in less developed countries and there is a considerable attention to produce activated carbon from less expensive and available materials. As a low-cost adsorbent, activated carbon can be produced from materials such as rice husk, seeds husk, tea leaves, sawdust, oil palm shell, coconut husk and coconut shell.14 Activated carbon is one of the most important adsorbents which is applied in different areas. In these areas it is important to determine and remove low concentrations of some pollutants, such as heavy metals. Very good features of this adsorbent are the main reason why it is u, Praškast ugljenični materijal proizveden iz kokosove ljuske korišćen je kao adsorbent za uklanjanje Cr(VI) jona iz vodenih rastvora. Karakterizacija adsorbenta rađena je primenom dve analitičke tehnike, skenirajućom elektronskom mikroskopijom (SEM) i BET metodom. Eksperimenti adsorpcije rađeni su u šaržnom režimu, kako bi se istražili uticaji pH rastvora, vremena kontakta i početne koncentracije Cr(VI) jona. Eksperimentalni rezultati su pokazali da je efikasnost uklanjanja Cr(VI) najveća u pH intervalu od 2,0 do 3,5, a da se ravnoteža uspostavlja nakon 60 minuta. Dva ravnotežna adsorpciona modela, Langmirov i Frojndlihov, korišćena su za fitovanje dobijenih podataka. Frojndlihova izoterma je obezbedila najbolju korelaciju za adsorpciju Cr(VI) jona na ugljeničnom materijalu proizvedenom iz kokosove ljuske. Na osnovu dobijenih rezultata može se zaključiti da ugljenični materijal proizveden iz kokosove ljuske predstavlja jeftin i efikasan adsorbent koji bi potencijalno mogao biti korišćen za tretman otpadnih voda koje sadrže toksični Cr(VI).

Hazardous industrial wastes are the most common source of environmental pollution. Waters originating from unregulated landfills and places of inadequate disposal of this type of wastes can pollute the water sources and affect the human health. In this study, electroplating waste sludge (ES) and various Fe-rich wastes were used as starting materials for the synthesis of inorganic pigments. Obtained black Cr1.3Fe0.7O3 pigments possess adequate properties required for use as inorganic pigments.

An analytical method based on solid-phase extraction (SPE) using coconut shell activated carbon (CSAC) as a low-cost adsorbent and high performance liquid chromatography with diode array detector (HPLC-DAD) was developed and validated for the determination of four varying polarity pesticides in water samples. SPE procedure was optimized and under the optimized conditions the proposed method was validated. The method exhibited good linearity, satisfactory precision (1.4 – 5.1%), high enrichment factor, good recovery and low limits of detection (0.025 – 0.039 g/dm3 ). Optimized method was used to determine selected pesticides in tap water samples. The recoveries ranged from 58.2% to 105.3%, with low relative standard deviations. The obtained results indicated that the proposed SPE-HPLC-DAD method could be efficiently used for the determination of the selected pesticides in environmental water samples at trace levels.

Primena apatitnih materijala kao aditiva kontaminiranom zemljištu jedna je od intenzivno proučavanih metoda in situ stabilizacije radionuklida u zemljištu. Istraživanja uticaja tretmana na distribuciju Mn u zemljištu i njegovu biodostupnost su posebno interesantna, s obzirom da je ovaj element esencijalan za biljke. U ovom radu ispitan je efekat različitih doza biogenog apatita (0,3%, 2% i 5%) kao aditiva kiselom zemljištu, na frakciju biodostupnog Mn hemijski ekstrahovanog metodom DTPA, kao i na sadržaj Mn u nadzemnom delu biljke Lolium perenne gajene u pot-eksperimentima na netretiranom i tretiranom zemljištu. Ustanovljeno je da se sa povećanjem količine dodatog bioapatita smanjuje koncentracija Mn u DTPA ekstraktu, kao i u nadzemnom tkivu biljke. Hemijski ekstrahovane i biološki usvojene koncentracije Mn su međusobno bile u pozitivnoj korelaciji (R2=0,971, p<0,05). U svim varijantama tretmana DTPA ekstrakt je sadržao koncentracije Mn u granicama koja se smatraju adekvatnim za većinu biljnih kultura., The use of apatite materials as additives to contaminated soil is one of the intensively studied in situstabilization methodforradionuclides in thesoil.Investigation of the treatment effects on the Mn distribution in the soil and its bioavailability are particularly interesting, since this element is essential for plants.In this paper, the effect of various doses of biogenic apatite (0.3%, 2% and 5%) as an additive to acid soil, was investigated in relation to the bioavailable Mn fractionchemically extracted by DTPA methodand to the Mn content in the above-ground part of the Lolium perenneplant, cultivated on untreated and treated soils in pot experiments. It was found that the increase in the amount of added bioapatite decreases the concentration of Mn in the DTPA extract, as well as in the above-ground tissue of the Lolium perenneplant.Chemical extracted and biologically accepted Mn concentrations were in positive correlation (R2= 0.971, p <0.05).In the all treatment variants, the DTPA extractscontained Mn concentrations within the limits considered to be adequate for most plant cultures.

The limestone and lime are agents widely used for separation of toxic metals from contaminated water. To reduce the exploitation of natural limestone deposits, appropriate replacements are sought out among the waste materials and by-products. Seashells, accumulated as an abundant waste in coastal areas, have high content of calcium carbonate and so far have shown high efficiency in neutralization and metal immobilization processes. In this study, the removal of Cu(II) ions was investigated using grounded seashell waste (a) without any pretreatment and (b) exposed to temperature treatment in the range 300-900 degrees C. The influence of temperature on the mineral phase transformation, solution pH and the removal efficiency of Cu(II) ions was monitored. Treatments at T gt 500 degrees C exhibit positive effect on Cu(II) separation, with the samples partially or completely converted to calcium oxide being the most effective in the entire Cu(II) concentration range (6.34-639 mg/L). The efficiency of Cu(II) removal was largely associated with the effect on solution pH. The two level full factorial design was used to evaluate the significance of seashell composition (calcium carbonate vs. calcium oxide), granulation, dose and contact time, on the separation of Cu(II) and other cationic pollutants (Fe, Zn, Ni and Pb) from wastewater. The seashell dose and granulation, as well as their interaction, were generally the most influential factors. The variations in the levels of investigated factors had a substantial effect on the process through the indirect effect onto the solution pH. More than 99% of Cu(II) ions were separated at pH gt 7, while the final pH range 8.2-12.2 was found optimal for total metal separation (97.6-98.9%).

The limestone and lime are agents widely used for separation of toxic metals from contaminated water. To reduce the exploitation of natural limestone deposits, appropriate replacements are sought out among the waste materials and by-products. Seashells, accumulated as an abundant waste in coastal areas, have high content of calcium carbonate and so far have shown high efficiency in neutralization and metal immobilization processes. In this study, the removal of Cu(II) ions was investigated using grounded seashell waste (a) without any pretreatment and (b) exposed to temperature treatment in the range 300-900 degrees C. The influence of temperature on the mineral phase transformation, solution pH and the removal efficiency of Cu(II) ions was monitored. Treatments at T > 500 degrees C exhibit positive effect on Cu(II) separation, with the samples partially or completely converted to calcium oxide being the most effective in the entire Cu(II) concentration range (6.34-639 mg/L). The efficiency of Cu(II) removal was largely associated with the effect on solution pH. The two level full factorial design was used to evaluate the significance of seashell composition (calcium carbonate vs. calcium oxide), granulation, dose and contact time, on the separation of Cu(II) and other cationic pollutants (Fe, Zn, Ni and Pb) from wastewater. The seashell dose and granulation, as well as their interaction, were generally the most influential factors. The variations in the levels of investigated factors had a substantial effect on the process through the indirect effect onto the solution pH. More than 99% of Cu(II) ions were separated at pH > 7, while the final pH range 8.2-12.2 was found optimal for total metal separation (97.6-98.9%).