Characterization of waste computers processors and proposal of the metals valorization process

Given the constant development of the high-tech industry, consumer-oriented societies, and reduced electronic equipment's lifespan, the outcome of growth and accumulation of waste is inevitable. Yet, specific electronic equipment components, such as central processing unit (CPU), are carriers of valuable metals, primarily precious, so waste electronic equipment become of recyclable interest. However, inadequate technological processing, particularly in the informal recycling sectors, leads to valuable metals losses. This approach has a negative economic and environmental impact: valuable material is usually considered as waste and landfilled with metals trapped in it, while due to increasing demand, metals are being exploited from natural resources. In this sense, there is an unquestionable need for an innovative recycling approach and adequate waste management that would lead to i) the decrease of natural exploitation, ii) the removal of waste accumulated in the environment, and iii) better utilization of material flows. The aim of this paper is an evaluation of the potential of waste CPU acid leaching residue as secondary material and the proposal of the innovative design of an adequate technological process for CPU recycling and recovery of valuable metals while minimizing their loss. The first part of the study included the characterization of the CPU acid leaching residue. Results of the research point out that precious metals content is significant, and material could be further exploited as secondary raw material. However, further optimization of process parameters is needed to achieve the most efficient valorization. A conceptual proposal of the technological scheme for metal recovery is given in the second part, considering two approaches: hydro- and pyrometallurgical methods. An innovative approach for recycling and waste management can contribute to the ultimate goal nowadays globally set as an imperative: achieving a circular economy through improved material flows management

Recyclability of technology metals from e-waste: case study of In and Ga recovery from magnetic fraction

This study presents the results of the theoretical assessment and a preliminary experimental investigation of technology metals (TM) recovery from magnetic fraction obtained after mechanical treatment of waste printed circuit boards (WPCBs). Experimental work included physical and chemical characterization, thermodynamic analysis, and pyrometallurgical tests corresponding to secondary lead, copper, and steel metallurgy. Technology metals recyclability and recovery potential were evaluated with respect to their distribution between metal and slag phase (difficult for recovering) versus the dust phase (easy for recovering). According to obtained results, it was determined that high-temperature processing of magnetic fraction in the electric arc furnace promotes volatilization of the TM and their pre-concentration in the filter as a dust product from which they could be valorized using further hydrometallurgical methods

Promene linearnih i nelinearnih mera nizova RR i QT intervala posle uzimanja piva

BACKGROUND: /Aim. There are only several studies on the acute effect of alcoholic drinks intake on heart rhythm and this phenomenon is still not well understood. We wanted to examine whether linear and nonlinear measures of RR interval and QT interval series could quantify the effect of beer in healthy subjects. Methods. Eighteen young volunteers drank 500 mL of beer (21 g of ethanol). Electrocardiogram (ECG) recordings were taken in supine position: 20 minutes before (relaxation) and 60 minutes after drink intake. The RR interval series and the QT interval series were extracted from ECG and we calculated short-term (α1) and long-term (α2) scaling exponents and sample entropy (SampEn) for both series; low frequency (LF) and high frequency (HF) spectral components from RR interval series and QT variability (QTV). Blood pressure was measured every 10 minutes. Results. It was shown that beer induced changes in variability and correlation properties of these series. Immediate effect of beer intake was detected as a transient increase in the QT variability, heart rate and blood pressure. Delayed effects of beer were shortening of the RR and QT intervals and reduction of the HF spectral component. Beer intake also increased short-term scaling exponent (α1) of the RR time series and long-term scaling exponent (α2) of the QT time series. Conclusion. Our results suggest that acute effects of beer are reduced parasympathetic control of the heart and changed dynamic complexity of the ventricular repolarization.Uvod/Cilj. Akutni efekat uzimanja alkoholnih pića na kardiovaskularne ritmove je fenomen koji još uvek nije dovoljno razjašnjen i u literaturi postoji svega nekoliko radova na tu temu. Cilj rada je bio da se ispita da li se linearnim i nelinearnim merama nizova RR i QT intervala može kvantifikovati akutni efekat male količine piva kod zdravih osoba. Metode. Osamnaest mladih zdravih muškaraca je pilo po 500 mL piva (21 g etanola). Elektrokardiogram (EKG) je beležen u ležećem položaju: 20 minuta pre (u relaksaciji) i 60 minuta neposredno posle uzimanja pića. Iz digitalizovanog zapisa EKG-a izdvojeni su nizovi RR i QT intervala. Iz oba niza smo izračunali kratkodometni (α1) i dugo-dometni skalirajući eksponent (α2), kao i entropiju uzorka (SampEn). Iz nizova RR intervala određene su spektralne komponente niskofrekventnih (LF) i visokofrekventnih (HF) opsega, a iz nizova QT intervala varijabilnost QT intervala (QTV). Krvni pritisak je bio meren svakih 10 minuta. Rezultati. Pokazali smo da pivo menja varijabilnost i korelacione osobine ovih nizova. Neposredni efekat uzimanja piva ogleda se u prolaznim povećanjima QT varijabilnosti, srčane frekvence i krvnog pritiska, a produženi u skraćenju dužine RR i QT intervala i smanjenju spektralne komponente HF. Uzimanje piva je takođe dovelo do porasta kratkodometnog skalirajućeg eksponenta (α1) RR niza i dugodometnog skalirajućeg eksponenta (α2) QT niza. Zaključak. Akutni efekat uzimanja piva je redukovana parasimpatička kontrola srca i izmenjena kompleksnost dinamike ventrikularne repolarizacije

Effect of the Deposition of Vanadium-Oxide on the Photocatalytic Activity of TiO2 Nanotubes and Its Photodiode Performance Interfaced with CH3NH3PbI3 Single Crystal

In this study, we report the influence of vanadium oxide (VO), as a photosensitive component, on the photoactivity of TiO2 nanotubes (TNTs). A series of TNTs of varying tube diameter were synthesized by the anodization of titanium foils at different voltages, while vanadium oxide was deposited on TNTs by wet chemical deposition. An improvement in the optical properties of nanotubes was observed after the deposition of vanadium oxide. An improvement in the optical properties (redshift in UV-Vis spectra) of TNTs and TNT/VO was noted. The photocatalytic activity was improved with increasing tube diameter, while it was weakened after the deposition of VO. Furthermore, photoactivity was investigated in photodiodes based on TNTs or TNT/VO and single crystals of CH3NH3PbI3. The photoelectric measurement revealed that different TNT diameters did not influence the I-V characteristic of the photodiodes, while the deposition of VO improved the photocurrent for smaller TNTs

Effect of the Deposition of Vanadium-Oxide on the Photocatalytic Activity of TiO₂ Nanotubes and Its Photodiode Performance Interfaced with CH₃NH₃PbI₃ Single Crystal

In this study, we report the influence of vanadium oxide (VO), as a photosensitive component, on the photoactivity of TiO2 nanotubes (TNTs). A series of TNTs of varying tube diameter were synthesized by the anodization of titanium foils at different voltages, while vanadium oxide was deposited on TNTs by wet chemical deposition. An improvement in the optical properties of nanotubes was observed after the deposition of vanadium oxide. An improvement in the optical properties (redshift in UV-Vis spectra) of TNTs and TNT/VO was noted. The photocatalytic activity was improved with increasing tube diameter, while it was weakened after the deposition of VO. Furthermore, photoactivity was investigated in photodiodes based on TNTs or TNT/VO and single crystals of CH3NH3PbI3. The photoelectric measurement revealed that different TNT diameters did not influence the I-V characteristic of the photodiodes, while the deposition of VO improved the photocurrent for smaller TNTs