Environmental status of marine plastic pollution in Spain

The excessive use of plastic in our society is causing a massive accumulation, since it is a non-biodegradable product and with still poor recycling rates. This effect can be observed in the seas, which more and more plastic waste are accumulating. The present work is a critical review, based on all currently available literature, that reports environmental status of marine plastic pollution, especially microplastic pollution, in Spain. The three Spanish water areas with the highest presence of plastics are the Alboran Sea, the Gulf of Alicante and the vicinity of Barcelona probably related to fishing and industrial activities and high population densities. With regard to microplastic contamination on beaches in Spain, annual monitoring by the Spanish government shows contamination along the entire coast of the country, with particularly high concentrations in the Canary Islands (between 800 and 8800 particles/m2 in spring). Between 40 and 50% of the particles analyzed were pellets and the main factors postulated for the distribution of these particles are marine currents and the geomorphological characteristics. With regards to biota, ingestion of microplastics by fish has been intensely confirmed and, important differences were observed between the locations of the sampling, being bogues (Boops boops) one of the fish species more studied in Spain. Finally, the work includes a revision of European and Spanish legislation about plastics and marine pollution and some strategies to reduce this kind of contamination in Spain

COVID-19 personal protective equipment (PPE) contamination in coastal areas of Granada, Spain

This research was funded by project “RECOMAR” (PYC20 RE 041 UGR), co-financed 80 % by the ERDF, ERDF Operational Program 2014- 2020 and the Ministry of Economic Transformation, Industry, Knowl- edge and Universities, Junta de Andalucía. European Union – European Regional Development Fund (ERDF) - “Andalusia moves with Europe”. Authors thank “Commonwealth of Municipalities of the Tropical Coast of Granada” that greatly assisted the sampling campaigns. Funding for open access charge: Universidad de Granada / CBUA.The use of disposable personal protective equipment (PPE) as a control measure to avoid transmission against COVID-19 has generated a challenge to the waste management and enhances plastic pollution in the environment. The research aims to monitor the presence of PPE waste and other plastic debris, in a time interval where the use of face mask at specific places was still mandatory, on the coastal areas of Granada (Spain) which belongs to the Mediterranean Sea. Four beaches called La Rijana, La Charca, La Rábita and Calahonda were examined during different periods. The total amount of sampled waste was 17,558 plastic units. The abundance, characteristics and distribution of PPE and other plastic debris were determined. Results showed that the observed amount of total plastic debris were between 2.531·10−2 and 24.487·10−2 units per square meter, and up to 0.136·10−2 for PPE debris, where face masks represented the 92.22 % of the total PPE debris, being these results comparable to previous studies in other coastal areas in the world. On the other hand, total plastic debris densities were in the range from 2.457·10−2 to 92.219·10−2 g/m2 and densities were up to 0.732·10−2 for PPE debris. PPE debris supposed 0.79 % of the weight of total waste and the 0.51 % of total items. Concerning non-PPE plastic waste: cigarettes filters, food containers and styrofoam were the most abundant items (42.95, 10.19 and 16.37 % of total items, respectively). During vacation periods, total plastic debris amount increased 92.19 % compared to non-vacation periods. Regarding type of beaches, the presence of plastic debris was significantly higher on touristic/recreational than in fishing beaches. Data showed no significant differences between accessible and no-accessible beaches, but between periods with restrictive policy about mask face use and periods with non-restrictive policy data suggest significant differences between densities (g/m2) for PPE litter. The amount of PPEs debris is also correlated with the number of cigarettes filters (Person's r = 0.650), food containers (r = 0.782) and other debris (r = 0.63). Finally, although interesting results were provided in this study, further research is required to better understand the consequences of this type of pollution and to provide viable solutions to this problem.Project “RECOMAR” (PYC20 RE 041 UGR), co-financed 80 % by the ERDF, ERDF Operational Program 2014- 2020 and the Ministry of Economic Transformation, Industry, Knowl- edge and Universities, Junta de Andalucía. European Union – European Regional Development Fund (ERDF) - “Andalusia moves with Europe”Funding for open access charge: Universidad de Granada / CBU

Laboratory-Scale Optimization of Celestine Concentration Using a Hydrocyclone System

A pilot hydrocyclone plant was used to concentrate medium-grade celestine ore (67% celestine) from the Montevive deposit in Granada (Spain) by using a dense media concentration (DMS) process. To optimize the concentration process, several types of heavy minerals (coarse, fine C40 ferrosilicon and/or magnetite) were used to prepare a dense media with a constant density of 3.0 kg/L. Then, the dense media (loaded with run-of-mine celestine mineral) was fed into the hydrocyclone system. The mineral was then separated into two streams, the first containing the mineral fractions that float (over stream) and the second containing fractions that sink (under stream) in the dense media. Next, the heavy minerals (ferrosilicon and/or magnetite) were recovered from the dense media using magnetic separation. The celestine mineral recovered from each stream was divided into two fractions with particles size above or below 250 m to study the effect of the mineral particle size on the separation process. Their mineral composition was quantified by X-ray diffraction (XRD) using the Rietveld method. The celestine is preferentially concentrated in the under stream in the mineral fraction with particles larger than 250 m (up to 90% celestine). The optimum results (highest % of celestine) were obtained after desliming and using the ferrosilicon C40 medium, which has the smallest particle size (<40 m) of all media used. The results of this study show that medium-grade celestine mineral accumulated in the mine tailings can be efficiently concentrated using a DMS process, which could help in making mine operations more sustainable and eco-friendlier.CNT 5589 (University of Granada)MineTheGap (European Union) CELABDEN PROJEC

Testing of New Collectors for Concentration of Fluorite by Flotation in Pneumatic (Modified Hallimond Tube) and Mechanical Cells

Authors acknowledge to MINERA DE ÓRGIVA, S.L. company for their economic and technical support and collaboration in the experimental tests.In this study, two new collectors for fluorite flotation DP-OMC-1033 (DP-I) and DP-OMC-1234 (DP-II) were tested and compared with oleic acid (OA), sodium oleate (SO) and potassium oleate (PO). According to fluorite grade and fluorite metallurgical recovery, the effect of each collector was determined, both in mechanical and pneumatic cell flotation. The effect of temperature on the collectors from 25 to 55 ◦C was studied. Flotation tests showed that the best results in terms of fluorite metallurgical recovery were 82.8% and 87.9% for new collectors DP-I and DP-II respectively, for a dosage of 100 g/t and using pneumatic cell. Additionally, in terms of fluorite grade, DP-I showed the best results, achieving 79.7% of CaF2 in roughing step for a dosage of 100 g/t. Fluorite metallurgical recovery and grade in concentrate increased for OA, SO and PO with increasing temperature. However temperature did not have a significant effect on both metallurgy recovery and CaF2 grade using DP-I and DP-II, so the process can be effective at 25 ◦C reducing operating costs.Company MINERA DE ORGIVA, S.L., Spai

Life cycle assessment of mechanical recycling of post-consumer polyethylene flexible films based on a real case in Spain

Mechanical recycling of plastic waste is a common practice in industry and is an environmental solution to the problem of plastics disposal. In this article, a case study of mechanical recycling of post-consumer polyethylene flexible films in Granada (Spain) was analyzed from an environmental point of view by the Life-Cycle Assessment methodology. The industrial process is divided into four large areas of operation: sorting, washing, extrusion and wastewater treatment. The results show that the washing area has the largest environmental impacts, mostly due to the electricity consumption, followed by sorting. Also, the overall mechanical recycling process causes damage, mainly, on human health, which dominates over ecosystems and resources with 93.4% of the total impact of the process. Two different scenarios have also been considered for the generated waste, and they critically affect the overall environmental performance of the entire process. The first scenario considers the impacts of the landfill disposal of the humid organic matter generated and the losses of PE. In this scenario, all the CH4 resulting from the anaerobic degradation of organic matter was emitted into the atmosphere. In this case, human health impact was high. In the second end-of-life scenario, all the CH4 generated would be captured and burned in a gas turbine for energy generation. Lower impacts were found in human health and ecosystems categories, as well as the total value, in the second scenario.This work has received funds from the European Union– LIFE Programme, under Grant Agreement LIFE17ENV/ES/000229. Funding for open access charge: Universidad de Granada / CBUA

Performance of Different Catalysts for the In Situ Cracking of the Oil-Waxes Obtained by the Pyrolysis of Polyethylene Film Waste

The author Lucía Quesada acknowledges the financial support provided by the Ministry of Education (Spain) through Research Grant FPU18/01293.Currently, society is facing a great environmental problem, due to the large amount of plastic waste generated, most of which is not subjected to any type of treatment. In this work, polyethylene film waste from the non-selectively collected fraction was catalytically pyrolyzed at 500 ◦C, 20 ◦C/min for 2 h, in a discontinuous reactor using nitrogen as an inert gas stream. The main objective of this paper is to find catalysts that decrease the viscosity of the liquid fraction, since this property is quite meaningful in thermal pyrolysis. For this purpose, the three products of catalytic pyrolysis, the gaseous fraction, the solid fraction and the liquid fraction, were separated, obtaining the yield values. After that, the aspect of the liquid fraction was studied, differentiating which catalysts produced a larger quantity of waxy fraction and which ones did not. The viscosity of these samples was measured in order to confirm the catalysts that helped to obtain a less waxy fraction. The results showed that the zeolites Y and the zeolites β used in this study favor the obtaining of a compound with a smaller amount of waxes than for example catalysts such as FCC, ZSM-5 or SnCl2.Ministry of Education (Spain) FPU18/01293Department of Chemical Engineering, University of Granad

Characterization and Use of Char Produced from Pyrolysis of Post-Consumer Mixed Plastic Waste

In this work, the pyrolysis of post-consumer mixed plastic waste (polypropylene (PP), polystyrene (PS) and polyethylene film (PE)) is carried out. The solid product of the pyrolysis is characterized and tested for its use as adsorbent of lead present in aqueous media. The pyrolysis temperature has a great influence on the solid product yield, decreasing when the temperature increases. The highest yield to solid product obtained is from the pyrolysis of film at lower temperature (450 ◦C), reaching almost 14%. The results of product solid characterization reveal that the carbon, hydrogen and nitrogen content decreases with increasing pyrolysis temperature. Furthermore, both the ash and the volatile content are related to the pyrolysis temperature. The ash content is higher when the pyrolysis temperature is higher, while when the temperature increases, a solid product with lower volatile content is obtained. In respect to specific surface area, a higher pyrolysis temperature improves the properties of the solid product as an adsorbent. The adsorption capacity increases as the pyrolysis temperature increases, with the highest value of 7.91 mg/g for the solid obtained in the pyrolysis at 550 ◦C. In addition, adsorption capacity increases as the initial concentration of lead rises, reaching a maximum value close to 26 mg/g for an initial concentration of 40 mg/L. The Sips model is the one that best reproduces the experimental results of the adsorption process equilibrium study.PID2019-108826RB-I00/SRA (State Research Agency)/10.13039/50110001103

Column Leaching Tests to Valorize a Solid Waste from the Decommissioning of Coal-Fired Power Plants

The authors are grateful to the Minera de Órgiva, S.L., Granada, Spain for financial support, supply of materials used for experiments and approval of this work for publication. Also, authors would like to thank to Celso Amor for his helpful advice on various technical issues oriented to scale-up.Solid waste from the decommissioning of coal-fired power plants collected from a power plant in Spain (Puertollano, Ciudad Real) was subjected to acid leaching tests in columns to evaluate the leachability of several valuable and toxic metals (Al, Ca, Fe, K, Mg, Na, Ti, V, Cr, Mn, Ni, and Zn). First, the contaminated waste, delivered by a national company, was chemically characterized. Second, column-leaching tests were conducted using two different acid solutions (nitric and sulfuric acid). The effect of the leaching agent concentration and time of leaching were examined. The results of column leaching tests showed that different concentrations of the acid solutions leached different proportions of Al, Fe, Mg, Mn, Ni, V, and Zn, which were leached by acid solutions from the solid waste sample. In general, use of sulfuric acid at pH 0.5 resulted in better leaching. Next, a comparison between three different configurations (one single stage without recirculation, one single stage with total recirculation of leachate and leaching in two consecutive stages: one with total recirculation of leachate and another one with acid set to a pH value of 0.5 and without recirculation) was performed. At the end of the experiments, all leaching methods resulted in comparable yields for Al (0.36–0.48%), Fe (5.99–6.40%), Mg (4.43–5.11%), Mn (2.71–2.83%), Ni (12.08–12.75%), V (0.08–0.34%), and Zn (23.62–25.28%). However, better results were obtained when two consecutive stages were carried out. Additionally, the effect of forced aeration on leachability was studied. Finally, this investigation showed that hydrometallurgical treatment of contaminated solid by means of acid leaching followed by basic leaching and a water wash between these stages was a potentially feasible method for reducing hazardous levels of the residue.This research was funded by MINERA DE ÓRGIVA, S.L

Recovering Metals from Aqueous Solutions by Biosorption onto Hydrolyzed Olive Cake

Olive cake obtained as a by-product from the olive oil industry has been evaluated as biosorbent of heavy metals from aqueous solutions in batch and continuous systems (fixed-bed columns). First, a complete study of effect of hydrothermal treatment with water on biosorption capacity of resulting solid was performed. Results showed that the values of biosorption capacity increased when the particle size of material decreased and the temperature of treatment increased. Then, hydrolyzed olive cake was treated by common chemicals (hot water, nitric acid, and sodium hydroxide) and the impact of chemical treatment was analyzed. The results were well reproduced by Langmuir and Freundlich isotherm models, getting maximum experimental biosorption capacities that changed between 42.34 mg/g obtained for the solid material modified by NaOH and 14.27 mg/g obtained for the solid material modified by nitric acid. Finally, laboratory tests in fixed-bed columns were performed with four different heavy metals and at three different inlet concentrations. The biosorption capacity increased from 2.83 mg/g (Cr), 4.51 mg/g (Cu), 12.30 mg/g (Pb), and 4.10 mg/g (Zn) to 3.08 mg/g (Cr), 5.17 mg/g (Cu), 13.21 mg/g (Pb), and 5.51 mg/g (Zn) when the concentration of metal ions increased, from 50 mg/L to 200 mg/L, respectively. Also, the experimental data obtained was successfully correlated with the Thomas, Yoon–Nelson, and dose–response models.All authors are grateful to the Spanish Ministry of Economy, Industry and Competitiveness for financial support received (Project CTM2016-75977-R)

Recovery, separation and production of fuel, plastic and aluminum from the Tetra PAK waste to hydrothermal and pyrolysis processes

The establishment of a method of separation of materials from Tetra Pak waste to obtain products for use as raw material, fuel or other purposes was investigated in this study. First, the feasibility of hydrothermal treatment for the production of a solid fuel (hydrochar) and solid fraction formed by polyethylene and aluminum, called composite was analyzed. The results indicated that hydrothermal treatment performed at 240 ◦C yield the formation of hydrochar with good properties for its use as fuel and a composite of polyethylene and aluminum. The best conversion and separation of the cardboard and polyethylene/aluminum were obtained using 120 min as operating time. Then, the recovery of the aluminum fraction from the composite by using spent olive oil waste was studied. A partial separation of the composite layers (polyethylene and aluminum) was accomplished with improved aluminum purity for higher operating temperatures. Finally, the operating conditions of the pyrolysis process for the production of a solid (char) and high purity composite (aluminum) were optimized. The characterization results indicated that both char and aluminum resulting from the pyrolysis of the Tetra Pak at 400 ◦C still have a significant amount of polyethylene while higher purity levels of aluminum can be obtained at temperatures equal of higher than 500 ◦C