Percentage Of Cu Research Articles

Polysulfone (Psf) Mixed Matrix Membrane incorporating Titanium Dioxide (TiO2)/Polyethylene Glycol (PEG) for the removal of copper

The global increasing contamination of water resources with toxic metals such as copper (Cu), poses severe threats to human health and aqueous ecosystems. Therefore, the ultrafiltration mixed matrix membranes (UF MMMs) possess an applicable approach for the removal of copper ions. This novel fabricated technology can be applied in various wastewater treatment systems for the removal of heavy metals, especially copper. MMMs were fabricated by blending polysulfone (Psf) with additives into the dope solution via the phase inversion method by incorporating titanium dioxide (TiO2) and polyethylene glycol (PEG) in Psf MMMs. Seven Psf MMMs samples labelled M0 to M6, each with its own formulation, were prepared and tested for density, porosity, and degree of Cu retention. MMMs were further characterized via Fourier transform infrared spectroscopy (FTIR), which revealed the range of the IR spectrum of Psf polymer membrane from 1319 cm-1 to 1600 cm-1, 1650 cm-1 to 3400 cm-1 for PEG, and 800 cm-1 to 3600 cm-1 for TiO2 NPs. As for the scanning electron microscopy (SEM), M6 (Psf/TiO2/PEG 6000) was found to be the most dense and highest porous morphology asymmetric Psf MMM. The retained percentage of Cu and flux for M6 attained the highest value of 80.3% and 136.99 L/m2 .h respectively, whereas for the neat Psf membrane, M0 exhibited the lowest retained percentage of Cu and flux, about 25.8% and 61.64 L/m2.h. The inclusion of pore former and additives has shown an improvement of 54.5% in the copper rejection. Moreover, M6 displayed the highest antifouling properties compared to other Psf MMMSs. This study proves that PEG and TiO2 additives have significant potential to improve membrane performance due to the highest percentage of Cu retained on the surface of the membrane as adsorptive separation on Psf MMMs.

Glass ceramics with different colours from granite wastes prepared by changing crystallisation temperature: Crystallisation and properties

Granite is a popular natural decorative material, and its production generates large amounts of waste. Therefore, researchers have paid close attention to the utilization of granite waste as a resource. In this work, glass-ceramic containing the same concentration of copper oxide were prepared from granite waste using a melting technique. The effects of different crystallisation temperatures on the valence of copper ions and the crystallisation of the glass-ceramics were carefully examined. The glass-ceramics crystallised at 724 °C, 783 °C, and 904 °C contained copper oxide (CuO), diopside (CaMgSi2O6), and clinoenstatite (MgSiO3). Meanwhile, those crystallised at 987 °C and 1080 °C contained richterite ((Na, F)syn (Na(Na, Ca)Mg5Si8O22F2)) and cuprite (Cu2O). The crystallisation temperature influenced the valence state of copper ions in the glass-ceramics, as demonstrated by X-ray photoelectron spectroscopy (XPS). Not only was the Cu+ content heterogeneous among samples crystallised at the different temperatures heterogeneous, but the samples also exhibited dissimilar colours. The atomic percentage of Cu+ ions (ACu+) in the sample crystallised at 987 °C was higher than that in the other samples. The mechanical properties of the sample crystallised at 1080 °C included a bending strength of 127.14 MPa and a Vickers hardness of 8.16 GPa.

Impact of adding Na2SiF6 on the crystal phase and copper valence state in glass ceramics made from leftover granite for use as architectural ornamentation

Abstract The accumulation of granite waste can result in the occupation of a considerable amount of land resources. Using granite waste as glass ceramics for architectural decoration represents a potential solution to this issue. The microstructure, valence state, and crystalline phase of copper ions were examined by using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). The findings demonstrated that the concentration of Na2SiF6 affects the valence condition of Cu ions in crystallized glass. The crystalline phases of the sample containing 1.84 wt% Na2SiF6 consisted of forsterite (MgSiO3) and diopside (CaMgSi2O6), and the Cu+ accounted for 39.9% of the total Cu ions in the sample which showed a grey-black color. For the sample containing 3.67 wt% Na2SiF6, the crystalline phases consisted of richterite (Na, F) syn (Na (Na, Ca) Mg5Si8O22F2), cuprite (Cu2O), and forsterite, its Cu+ accounted for 39.9%, and the sample appeared orange-red. With the increase of Na2SiF6 content, the percentage of Cu+ in the total Cu ions showed an increasing trend, and the corresponding red color of the samples gradually deepened.

Fabrication and Evaluation of Thyroid Shield from Silicone Rubber-Cooper and its Comparison to Tube Current Modulation in CT Examination

This study aimed to fabricate thyroid shields made from Silicone Rubber (SR)-Cooper (Cu) material, analyze the effectiveness of SR-Cu shields in reducing radiation dose, and compare them with tube current modulation (TCM) in computed tomography (CT) examination. Thyroid shields were made from SR-Cu with Cu percentages of 0, 5, 10, 15, and 20%. The thyroid shields were positioned over the neck of the anthropomorphic phantom. Scanning was performed using a GE 128-slice CT scanner with fixed tube current of 150 mA and tube current modulation (TCM). The elatiscity of thyroid shields was tested using an universal testing machine (UTM). The ability of thyroid shields for dose reduction was measured using a 10X6-3CT Radcal detector, and quality of the resulted images was characterized with metric of signal-to-noise ratio (SNR) at the anterior, posterior, and lateral areas of the neck area of anthropomorphic phantom. It is found that the elasticity of the thyroid shields increased from 0.09 to 0.12 N/mm2 for Cu percentages from 0 to 20%. The measured dose decreased as the percentage of Cu increased. 20% of SR-Cu was able to reduce the dose by 32.4% for the fix tube current. In comparison, the TCM technique reduced the dose by 44.5%. Therefore, dose reduction using the developed shields is lower than using TCM approach. It is also found that implementation of the thyroid shields did not reduce image quality significantly. It is found that there were no apparent artifacts in the images. The highest SNR was found in the image with 20% SR-Cu, which was 3.84. In comparison, the SNR using the TCM approach was 3.59. In conclusion SR-Cu shields were successfully developed and they reduced dose with relatively consistent of image quality.

The synergistic impact of graphene and copper on microstructure, corrosion behaviors and biocompatibility of a magnesium metal matrix composite in Hank's solution

BackgroundThis research aimed to explore the combined effects of graphene (Gr) and copper (Cu) in a magnesium metal composite (MMC) on its microstructure, biocompatibility, electrochemical, and immersion corrosion behaviors. MethodsThe MMCs were prepared using the mechanical stir-casting method. Alloys with a preset weight percentage of Gr (0.15 wt.%) and various weight percentages of Cu (0.5 and 1 wt.%) were produced with pure Mg as the matrix. Significant findingsThis study demonstrates that Gr and Cu enhance crystallinity and increase grain size in composite materials. The introduction of Gr into the magnesium matrix alone elevates the corrosion rate. However, there was a further addition of 0.5 wt.% Cu (0.5Cu) showed a slight reduction in grain size growth and corrosion rate. The addition of more copper (1 wt.% Cu (1Cu)) increases both grain size and the corrosion rate again. Cytotoxicity test results indicate that Gr and Cu enhance the cell viability of 3T3 fibroblasts in vitro. These findings shed light on the intricate interplay between Gr and Cu in the microstructure and corrosion resistance of Mg-based composites and inspire confidence in developing magnesium metal composites for clinical applications.

Synthesis and characterization of CuxCd1‐xS nanocrystals into functionalized nitrile butadiene rubber matrix

AbstractIntroductionPolymetallic sulfides and heterostructures like CdIn2S4, CdZnS2, CuxS‐NiySz, Cu2CoSnS4, CoNi2S4, Zn0.76Co0.24S have been fabricated with various shapes and forms for new applications. Ternary copper cadmium sulfides (CuCdS2) are a p‐type semiconductor with a direct band gap of about 2.4 eV forms very good nanocrystals like copper sulfide could be potentially applied to optical and electronic applications. Knowing that the SILAR synthesis, optical, paramagnetic, dielectric properties, and annealing of copper cadmium sulfides have not been sufficiently investigated, they are extensively analyzed and studied in the present work.ObjectivesCuxCd1−xS (x = 0, 0.5, and 1) nanoparticles have been synthesized on the base of functionalized nitrile butadiene rubber by SILAR method and characterized using scanning electron microscopy, x‐ray diffractometer, UV–visible spectroscopy, Fourier‐transform infrared spectroscopy, electron paramagnetic resonance spectroscopy, and Raman spectroscopy. Effects of cycles, reaction time, and precursor concentration on the particle size, crystal growth and structure, bandgap energy, dielectric and paramagnetic properties, elemental composition, and morphology were investigated.MethodsThe synthesis of CuxCd1−xS nanocrystals was carried out into the obtained functional polymer matrix by SİLAR method. The functional polymer (FNBR) is a dark brown powder which contains ‐PO(OH)2 and ‐OPO(OH)2 functional groups and does not dissolve in organic and inorganic solvents, can be used as a very good stabilizer of nanostructures. The synthesis of CuxCd1−xS/FNBR nanocompsite was carried out in 3, 5, and 15 cycles.Results and discussionIn the process of ternary sulfide formation, the nucleation rate of CdS was high at the beginning of the reaction, while the growth rate and stability of CuS were high in the later course of the reaction. The average crystallite size of the nancrystallites has been increased from 1.13 nm to 7.39 nm by the increasing of the number of cycles from 5 to 15, respectively. It is explained by the inclusion of copper in the composition and getting more stable material. Copper cadmium sulfide nanostructures demonstrate wide band gap energy (~3.7 eV) in this work which is explained by the formation of nanosized particles in a limited volume of FNBR matrix.ConclusionsThe synthesis of CuxCd1‐xS nanocrystals was carried out into the obtained functional polymer matrix by SİLAR method. Strong diffraction peaks corresponding to cubic CdS are found with low SILAR cycles. SEM images of CuxCd1−xS/FNBR nanocomposite show that the atomic percentage of Cu and Cd into the ternary sulfide is 20.19% and 0.61%, respectively. It is explained by the inclusion of copper in the composition and getting more stable material with low solubility products (Ksp) which is in good agreement with XRD results. The calculated band gaps are higher than that of bulk CdS, CuS, and CuCdS2. Larger band gap is usually reported for defects or structural disorders, which is in good agreement with XRD and Raman results.

Electrodeposition of Nanostructured Co–Cu Thin Alloy Films on to Steel Substrate from an Environmentally Friendly Novel Lactate Bath under Different Operating Conditions

A new lactate bath was proposed to deposit Co–Cu thin alloy films in nanostructure form onto a steel cathode. The deposition bath contained CuSO4.5H2O, CoSO4.7H2O, CH3CHOHCOOH, and anhydrous Na2SO4 at pH 10. The effects of [Co2+]/[Cu2+] molar ratios, lactate ion concentration, current density (CD), and bath temperature on cathodic polarization, cathodic current efficacy (CCE), composition, and structure of the Co–Cu alloys were investigated. The new bath had a high cathodic current efficiency of 85%, which increased with the applied CD. However, it decreased as the temperature increased. The produced coatings have an atomic percentage of Cu ranging from 19.8 to 99%. The deposition of the Co–Cu alloy belonged to regular codeposition. The Co content of the deposit increased with the amount of Co2+ ions in the bath, lactate concentration, and current density but decreased as the temperature increased. Cobalt hexagonal close-packed (HCP) and copper-rich, face-centered cubic (FCC) Co–Cu phases combine to form the polycrystalline structure of the electrodeposited Co–Cu alloy. The average crystallite size ranges between 46 and 89 nm. An energy dispersive X-ray (EDX) examination confirmed that the deposit contained Cu and Co metals. The throwing power and throwing index of the alkaline lactate bath were evaluated and found to be satisfactory.

Investigation of electrical conductivity and electromagnetic wave absorption capabilities of water hyacinth biocarbon impregnated with Cu atom

This paper discusses the impregnation of Cu atoms at carbonization temperature of water hyacinth bio carbon composite. This composite is used as an absorber of electromagnetic waves. Because the inference of electromagnetic waves can cause damage to other electronic equipment. In addition, electromagnetic wave radiation can cause various human health problems. The purpose of the research is to obtain a material that is able to absorb electromagnetic waves and increase electrical conductivity, impregnation of Cu atoms at carbonization temperature of water hyacinth bio carbon composite. The composite material uses a composition ratio of water hyacinth powder and phenol-formaldehyde of 30:70. The carburization temperatures used were 600 °C, 800 °C, and 1000 °C with a heat increase rate of 7 °C/minute. This study used Scanning Electron Micrograph (SEM), X-Ray Diffraction (XRD), LCR Meter, and vector network analyzer. The results show that the impregnation of Cu atoms at carbonization temperature can increase the area of the nanostructure, thereby increasing the formation of micropores in the composite. The higher the carbonization temperature, the percentage of Cu and carbon compounds can increase, while the percentage of crystal structure decreases. Impregnation of Cu atoms further strengthens the composite's absorption of electromagnetic wave radiation. Impregnation of Cu atoms in water hyacinth bio carbon composites at carbonization temperature can increase the electrical conductivity of the composite. The results of this research have potential applications in the electronics industry, batteries, and electrical devices, and can be used to protect devices from electromagnetic interference, especially in telecommunications and the medical field

Modeling Cu removal from aqueous solution using sawdust based on response surface methodology.

Copper (Cu), as one of the heavy metals widely used in industrial and agricultural activities, has a fundamental role in the pollution of water resources. Therefore, removing Cu from the aqueous solutions is considered an important challenge in the purification of water resources. Thus, in this study, sawdust with a diameter of 260-600 μm was used to remove Cu from the aqueous solutions. At first, sawdust was washed using distilled water and dried at laboratory temperature. Cu absorption experiments in closed conditions were performed based on the central composite design (CCD) model and with a range of initial Cu concentrations equal to 1-25 mgl-1. The amount of changes for other variables, including pH, time, and amount of sawdust, was equal to 2-10, 5-185 (min), and 5-25 (gl-1), respectively. After the completion of each test, the remaining Cu concentration in the solution was measured using atomic absorption, and the percentage of Cu removed was determined from the difference between the initial and final concentrations. The results showed that the CCD model has a favorable ability to predict Cu removal from the aqueous solutions (R2=0.90 and RSME=3.34%). Based on the Pareto analysis, contact time, the amount of sawdust, pH, and the Cu concentration had the most significant effect on removing Cu from the solution. Contact time, amount of sawdust, and pH were directly related, and the amount of dissolved Cu was proportional to the removal of Cu from the solution. Therefore, sawdust is desirable as a natural adsorbent, and the removal efficiency of Cu from solutions with low Cu concentration is very high (94%). In this regard, it is advised to use sawdust in the process of targeting Cu and heavy metals due to its low cost and availability.

Effect of Interlayer Composition on the Properties of Laser-Directed-Energy-Deposition-Based Additively Manufactured Copper-Stainless Steel Wall Structures

Laser-directed energy deposition (LDED) is one of the advanced techniques used for the sustainable manufacturing of engineering components with minimal material wastage and higher performance. This paper reports an investigation on LDED-based additive manufacturing of compositionally graded Copper (Cu)-stainless steel (SS) wall structures for improved performance of tooling components. Three different approaches, such as Cu-SS direct joint, 20% graded Cu-SS, and 50% graded Cu-SS, are used to build the wall structures. Optical microscopy of LDED-built graded samples reveals defect-free deposition of Cu-SS direct joint and 50% graded Cu-SS wall structures at identified process parameters, whereas the 20%-graded wall yields micro-cracks in the lower Cu region. The elemental distribution shows gradual traditions in the weight percentages of Cu and Fe along the built wall. Furthermore, the ultimate tensile strengths of the direct Cu-SS joint wall structure and the 50%-graded Cu-SS wall structure are higher than the strength of LDED-deposited Cu, while the 20%-graded Cu-SS wall structure has lower ultimate tensile strength than the strength of LDED-deposited Cu. Lower ultimate strength and failure in the lower-Cu zone of 20% graded Cu-SS wall structure can be attributed to the presence of micro-cracks in the Cu20SS80 zone of 20%-graded Cu-SS wall structures. The study establishes LDED as a technique for building multi-material components promoting sustainability in terms of manufacturing and component performance.

In situ formation of CuxO/ZnO photocatalysts for efficient simultaneous oxidation of As (III) and adsorption of As (V): Effect of Cu loading.

The introduction of Cu ions onto ZnO leads to alterations in the electrical, optical, and magnetic characteristics of ZnO. These transformations, in turn, result in heightened photocatalytic activity and enhanced stability when employed in the degradation of both organic and inorganic pollutants. Here, a novel photocatalytic-adsorbent system is developed using zinc oxide (ZnO) nanostructures modified with Cu (II) ions in an aqueous solution containing 40mg/L of As (III). The system utilizes UV-A light (365nm) as the irradiation source, and the weight percentage of Cu (II) in the composite varies from 0 to 20%. The experimental results reveal significant adsorption of As (III), ranging from 20 to 50%, depending on the solution's Cu (II) content. Remarkably, the ZnO10%Cu composite exhibits the highest photocatalytic activity, achieving 40% adsorption and complete oxidation of As (III) within 25min of irradiation. Characterization of the composite after the photocatalytic treatment reveals the effective adsorption of As (V) within its structure. Furthermore, no traces of Cu (II) ions are detected in the solution after the reaction, indicating their successful adsorption onto the ZnO surface as Cu (I) and Cu (II) ions. This research marks a significant advancement in harnessing innovative materials for efficient arsenic removal, offering promising insights into the development of novel photocatalytic-adsorbent systems.

Sintesis dan Karakterisasi Fotokatalis TiO2/Cu Menggunakan Lampu UV

Most of the energy consumed comes from non-renewable fossil fuel resources. Burning fossil fuels has been found to be a major cause of environmental pollution and greenhouse gas emissions, making it the most common energy source. Therefore, renewable and environmentally friendly energy resources are needed, namely sunlight. One way to utilize sunlight is to store it into hydrogen compounds. Hydrogen comes from water through a process of breaking down its molecules which is called water decomposition. Water decomposition uses sunlight and a semiconductor photocatalyst, such as TiO2. In this research, TiO2 doped with Cu metal has been synthesized using UV lamp irradiation. TiO2 has been successfully synthesized. XRD characterization to determine the structure of TiO2. TiO2 has an anatase crystal structure. Then XRF characterization is done to see the percentage of Cu that has been successfully doped. When exposed to a UV lamp for 1 hour, 0.347% Cu was successfully doped. When exposed to a UV lamp for 5 hours, 1.28% Cu was successfully doped.

Improving antibacterial ability of Ti-Cu thin films with co-sputtering method

Due to the resistance of some bacteria to antibiotics, research in the field of dealing with bacterial infections is necessary. A practical approach utilized in this study involves the preparation of an antibacterial thin film on the surfaces, which can effectively inhibit and reduce biofilm formation and bacterial adherence. In this study, we report the fabrication of bactericidal titanium (Ti) and copper (Cu) surfaces which involves a powerful co-sputtering method. This method provides a situation in which constituent elements are deposited simultaneously to control the composition of the thin film. Prepared samples were examined by energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), X-ray diffraction (XRD), atomic force microscopy (AFM), and contact angle measurements. To evaluate antibacterial behavior, we used two bacterial strains Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus). Antibacterial activity of the prepared sample was assessed by determining the number of colony-forming units per milliliter (CFU/ml) using a standard viable cell count assay. Results indicated that as the Cu concentration increased, the nanoscale surfaces became rougher, with roughness values rising from 11.85 to 49.65 nm, and the contact angle increased from 40 to 80 degrees, indicating a hydrophilic character. These factors play a significant role in the antibacterial properties of the surface. The Ti-Cu films displayed superior antibacterial ability, with a 99.9% reduction (equivalent to a 5-log reduction) in bacterial viability after 2 h compared to Ti alone against both bacterial strains. Field emission scanning electron microscopy (FE-SEM) images verified that both E. coli and S. aureus cells were physically deformed and damaged the bacterial cell ultrastructure was observed. These findings highlight that adding Cu to Ti can improve the antibacterial ability of the surface while inhibiting bacterial adherence. Therefore, the Ti14-Cu86 sample with the highest percentage of Cu had the best bactericidal rate. Investigation of toxicity of Cu-Ti thin films was conducted the using the MTT assay, which revealed their biocompatibility and absence of cytotoxicity, further confirming their potential as promising biomaterials for various applications.

Electrochemical recycling of diamond and precious metals from used diamond tools

The recycling of used diamond tools, which contain a large amount of unused diamond particles and precious metals, can not only realize the reuse of resources, but also reduce the pressure of environmental protection. In this paper, diamond particles were recovered by acid dissolution of aqua regia, and the current density, complexing agent concentration and pH value of the acid dissolution system were adjusted to recover Cu and Co by electrodeposition. Scanning electron microscope and energy spectrometer were used to study the changes of the composition and morphology of the plated layers, and the effects of the parameters such as current density, complexing agent concentration and pH on the organization and composition of the alloy plated layers were analyzed. The results showed that at the current density of 40 mA/cm², pH 4.5 and complexing agent concentration of 10 g/L, uniformly distributed, dense and moderately thick Cu-Co alloy plating was obtained, and the weight percentages of Cu and Co reached the peak respectively. The Cu and Co in the waste diamond tools can be recovered under this condition with good recovery effect.

Soret-Dufour Effects on The Waterbased Hybrid Nanofluid Flow with Nanoparticles of Alumina and Copper

The two-dimensional mathematical model ofwater-based hybrid nanofluid, where the nanoparticles of the model are alumina (Al2O3) and copper (Cu) is analyzed in this article. It describes the heat and mass transfer which are induced by concentration and temperature differences, respectively. The current mathematical model extended the works by implementing both directions of moving sheet in the boundary conditions: stretching and shrinking, and use the exponential variations of the sheet velocity, temperature, and concentration of the hybrid nanofluid at the sheet. The final numerical solutions can be obtained by implementing Matlab bvp4c, which involves the step of choosing the most reliable solution in an actual fluid situation. This selection technique on numerical solutions is known as stability analysis and only needs to apply when more than one numerical solution appears in the Matlab bvp4c program. Finally, the controlling parameters such as nanoparticle solid volume fraction, suction, shrinking/stretching, Soret and Dufour cause an increment or decrement in the flow, heat and mass transfer in the hybrid nanofluid. For the stable solution, fluid velocity becomes slower whereas temperature and concentration of the fluid increase when the percentage of Cu, as well as Al2O3, rises into the water. Moreover, in case of local Nusselt number and local Sherwood number it is proved that Soret effect is the opposite phenomenon of Dufour effect.

Polyacrylonitrile (PAN)/Freeze-dried Chitosan (FCS)-NaY zeolite triple layer nanostructure fibrous adsorptive membrane (PAN/FCS-NaY TNAM) for Cu(II) and Pb(II) ions removal from aqueous solutions

In this study, an innovative PAN/FCS-NaY TNAM was fabricated using an electrospinning technique for Cu(II) and Pb(II) removal from contaminated water. Top and bottom fibrous layers (M1) were fabricated using a combination of FCS and PAN blends. Middle layer (M2) was electrospun from pure PAN solution and loaded with NaY zeolite particles. The physicochemical properties of the material and fibrous samples were investigated through SEM, FTIR-ATR, DSC, AFM, DMTA analysis, and contact angle measurement. The effective parameters, including initial ions concentration, time, reusability, and pH on the dynamic adsorption performance of the prepared membrane and its stability in the aqueous medium for Cu(II) and Pb(II) ions removal were investigated at a pressure of 0.006 bar. Dynamic metal ions adsorption was modeled using dynamic filtration prediction models such as Thomas and Yoon-Nelson. The fabricated nanostructure fibrous membranes with the removal percentage of Cu(II) and Pb(II) ions (94.6% and 98.7%, respectively) under the optimal operating conditions (initial concentration: 50 ppm, time: 10 min, and pH: 4.6), high compatibility in modeling dynamic filtration (R2 > 0.99), high pure water flux (298 LMH), suitable reusability (four-cycle without significant reduction in adsorption) as well as long-term stability, can be as potential filters in water treatment applications.

Leaching of Cr, Cu, Ni, and Zn from different solid wastes: Effects of adding adsorbents and using different leaching solutions

The leaching of potentially toxic elements from different industrial solid wastes (ISWs) must be understood to manage the environmental concerns they pose. The objective of this research was to investigate the effect of clay mineral (bentonite) and nanoparticle (MgO) on potentially toxic elements (Cr, Cu, Ni, Zn) leaching in some ISWs, when they leached with different leaching solutions. The highest amount of Zn and Ni was leached from ceramic factory waste (CFW) and stone cutting wastes (SCW), respectively, while the highest amount of Cr was leached from leather factory waste (LFW). In ISWs, the leaching percentage of Cu, Ni, and Zn were up to 11.2%, whereas the greatest leaching percentage of Cr was 26.7% of the total content. The addition of bentonite and MgO decreased potentially toxic element leaching. The results of effluents speciation of SFW indicated that at the beginning of leaching with CaCl2, nitric acid, and citric acid, 75.1%, 84.1%, and 39.6% of Cr were in different forms of Cr (III), respectively, while at the end of leaching the percentage of Cr (III) species were decreased and Cr (VI) species were increased to 83.6%, 88.4%, and 93.4%, respectively. The addition of bentonite and especially MgO to the ISWs reduced the leaching of potentially toxic elements as well as reduced the percentage of Cr (VI) in the effluents of SFW. The findings suggested that bentonite has the potential to be a low-cost and environmentally acceptable adsorbent for minimizing the leaching of Cr and other potentially toxic elements from ISWs.

Solvothermal synthesis of CMTS quaternary semiconductor nanoparticles with a symmetric kesterite structure: The role of the autoclave filling factor

Copper manganese tin sulfide (CMTS) is one of the promising chalcogenide materials and a potential candidate as an absorber material to develop low-cost, ultrathin solar cells. CMTS (Cu2MnSnS4) quaternary semiconductor nanoparticles (NPs) were synthesized by a solvothermal method utilizing different autoclave filling ratios. The influence of the autoclave filling ratio on the structure, phase formation, morphology, composition and optical properties of the CMTS-NPs was studied using various experimental techniques. The autoclave was filled with a solution up to 50, 60 and 70 percent of the autoclave volume. According to the FESEM images, the CMTS-NPs are uniform, dense and spherical, with slight agglomeration. The CMTS particles have an average crystal size in the range of 31 to 40 nm for different autoclave filling ratios. The chemical composition for CMTS was obtained from SEM – EDX and it was found that the sample with 60% filling factor had the best structure, with the atomic percentages of Cu: 26%, Mn: 9%, Sn: 12%, and S: 53%, which are close to the optimal values. The XRD results showed that the composition of the product was close to the stoichiometry of CMTS, with a Kesterite structure. Investigation of different autoclave filling factors showed that 60% is an optimum filling rate to obtain the CMTS pure phase with high crystallinity. The CMTS particles had a broad absorption band in the whole visible range with a band gap of 1.38 eV, being promising for photovoltaic applications.

Investigation of biochar- modified biosand filter performance for groundwater treatment for drinking water purposes: A laboratory and pilot scale study

This study investigated the feasibility of improving the performance of biosand filter (BSF) using date palm biochar for groundwater treatment. The effect of date palm biochar placement (at the top, middle and bottom region of the filter media) on the modified biosand filter (MBSF) against BSF was investigated on a lab scale for simultaneous removal of Cu, Zn, Fe, Mn, NH4+, PO43−, NO3−, SO42−, Cl−, Na, Mg, K, turbidity, color, and total coliform from synthetic groundwater. Filters were charged intermittently twice per day for 90 days. The average removal percentage of Cu was 95.05 and 99.23 %, Zn was 99.99 and 100 %, Mn was 74.54 and 89.99 %, Fe was 60.18 and 78.94 %, NH4+ was 22.33 and 30.62 %, PO43− was 99.45 and 99.53 %, NO3− was 8.03 and 8.18 %, K was 16.33 and 16.41 %, Total coliform was 93.97 and 92.89 % and effluent pH was 8.03–8.18, for lab scale BSF and MBSF(D) respectively. Turbidity and color removal was 100 %, while no removal was observed for SO42−, Cl−, Na, and Mg in the lab-scale filters. Using biochar and positioning it at the bottom region of the filter media as in MBSF(D) showed significant removal for Mn and Fe. The pilot scale MBSF(D) showed earlier clogging (43 days) and reduced treatment percentage for contaminants in comparison to the lab scale MBSF(D), except for total coliform (100 % removal). After regeneration, effluent concentration still met WHO drinking water limits and was operational for 82 days on the lab scale MBSF(D) and 32 days on the pilot scale MBSF(D).

Reaction time influence on copper tin sulfide micro flowers for enhanced electrochemical hydrogen evolution reaction (HER) performance

Herein, we report the effective way to optimize the copper tin sulfide (Cu2SnS3) micro flowers via a simple hydrothermal method using different reaction times, which could enhance the fabricated electrocatalyst in electrochemical water splitting applications. The prepared Cu2SnS3 was identified by X-ray diffraction (XRD) analysis, which demonstrated the formation of triclinic phase Cu2SnS3 with a=0.664, b=1.151 and c=1.993 nm, respectively. Phase confirmation was further analyzed by using Raman and Fourier-transform infrared (FTIR) spectroscopy, which also demonstrated pure tetragonal copper tin sulfide (CTS) phase. The morphology of the copper tin sulfide (CTS) materials was explored with the help of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) studies, which confirmed crystalline nature of triclinic copper tin sulfide (CTS) 3D hierarchical micro flowers. The prepared electrocatalyst was further characterized employing Energy-dispersive (EDX) and X-ray (XPS) spectroscopy. It exhibited chemical composition of Cu2p, Sn3d, and S2p in stoichiometric ratio with an atomic percentage of Cu, Sn, and S being 37.5, 40.7, and 21.7%, respectively. CTS-16 h exhibited 151 mV to afford 10 mA/cm2 and 139 mV/dec Tafel slope value, which was demonstrated by electrochemical characterizations. Moreover, the efficient electrocatalyst of CTS-16 h exhibited 131.5 cm2 electrochemical active surface area, while the other catalysts such as CTS-4 h, CTS-8 h and CTS-24 h were 49.25, 67.5, and 107.5 cm2 respectively. The CTS-16 h electrode shows excellent stability towards long-term CA test for one day with 94% retention. Therefore, the overall result suggests that the synthesized material provided a new approach for the noble metal catalysts substitute, and it is a potential material for clean energy systems.