Search results for "Diffusion dialysi"
showing 10 items of 14 documents
Design, construction and operational results of a pilot plant for the treatment and valorization of pickling waste solutions
2021
An innovative hybrid technology for both minimizing the waste production and optimizing the pickling process through the continuous control of pickling baths composition has been proposed by means of a pilot-plant installed at the Tecnozinco Srl, Carini (PA) hot-dip galvanizing plant. The recovery process has been accomplished by coupling a diffusion dialysis (DD), where HCl is recovered, a membrane distillation (MD), where HCl is concentrated, and a reactive precipitation (RP), where metal ions are recovered as iron hydroxide and ammonium/zinc chloride solution, to be used in the fluxing baths of the plant. The pilot plant was commissioned and operated using synthetic HCl solutions first a…
Diffusion dialysis for HCl and heavy metals separation from highly concentrated pickling solutions
2019
Disposal of pickling waste solutions strongly affects hot-dip galvanizing industries’ economics and environmental footprint. Thus, the recovery of acid is an important step to enhance the process sustainability. Diffusion dialysis (DD) can be used to separate acids and heavy metals (e.g. iron and zinc) from pickling waters, promoting the circular use of such raw materials. In the present work, two DD modules, a laboratory scale unit operating in batch and a continuous operated large unit, equipped with Fumasep anionic exchange membranes were tested. Results obtained show that zinc and iron affect HCl recovery in opposite way, however reaching high recovery values. In particular, zinc consid…
Treatment of electroplating wastewater by combining membrane technologies and reactive precipitation process at pilot scale
2022
Experimental investigation and modeling of diffusion dialysis for HCl recovery from waste pickling solution
2019
Abstract Hydrochloric acid recovery from pickling solutions was studied by employing a batch diffusion dialysis (DD) laboratory test-rig equipped with Fumasep membranes. The effect of main operating parameters such as HCl concentration (0.1–3 M) and the presence of Fe2+ (up to 150 g/l) was investigated to simulate the system operation with real industrial streams. The variation of HCl, Fe2+ and water flux was identified. When only HCl is present, a recovery efficiency of 100% was reached. In the presence of FeCl2, higher acid recovery efficiencies, up to 150%, were observed due to the so-called “salt effect”, which promotes the passage of acid even against its concentration gradient. A 7% l…
Experimental investigation and modelling of diffusion dialysis for the recovery of waste acid solutions
2018
Pickling is widely used as a chemical pre-treatment method for cleaning metal surfaces before other surface treatments and it consumes large amount of acids and water
Experimental investigation and modelling of diffusion dialysis process for regeneration of acidic pickling solutions
2017
Pickling is one of the key steps in metal finishing industries, where HCl solutions are largely used thus generating significant amounts of spent waste solutions containing high concentrations of metals and acid. The recovery of acid from such waste solutions is thus one of the most beneficial steps for reducing the environmental and economical impact of these processes. Among several separation methods, diffusion dialysis (DD) is becoming more and more attractive thanks to the recent important advances in ion exchange membranes (IEMs) field and because of its clean nature and operational simplicity, low installation and operating costs and low energy consumption [1,2]. In the present work,…
Effective recovery of HCl and metals from pickling solutions by cutting-edge membrane technologies
2018
The pickling process is an essential step in the hot-dip galvanizing process.It is performed by immersing manufacturedsteel pieces inacid bathsin order todissolve the oxidized layers. During the pickling process, acid attacks metal oxides on the surface, dissolving them in the pickling bath. Thus, the efficiency of the pickling liquor decreases due to the accumulation of metal salts and the consumption of free acid in the solution. When hydrochloric acid is used,ferrous chloride is producedduring the pickling treatment, reaching concentrations up to 250 g/l, while the acid concentration decreases by 75-85%. A pickling bath in this condition is considered spent [1] due to thevery low picklin…
Novel poly (ionic liquid)-based anion exchange membranes for efficient and rapid acid recovery from industrial waste
2020
Abstract Owing to the less energy consumption, positive impact on the environment, and prospect of providing clean water resources, anion exchange membranes (AEMs) are promising materials for acid recovery from various industrial wastewater/effluent. Based on the diffusion dialysis process, AEMs selectively allow rapid proton permeation while efficiently retaining metal ions. To enhance the efficiency of the acid recovery process, precise control of macromolecular architecture and chemical composition that enables high hydrophilicity, proton conductivity through the membrane, and ion exchange capacity is required. In this direction, we report on the one-step fabrication of novel poly (ionic…
Application of diffusion dialysis in separation of sulfuric acid and copper from electroplating wastewater
Electroplating industry creates large volumes of wastewater that contain acids and heavy metallic ions which are toxic but valuable. Diffusion dialysis (DD) can be used to separate acids from heavy metals. In this work, two single-cell DD modules equipped with Fumasep FAD membranes were used for the first time for the separation of sulfuric acid from copper. The first module consisted of a laboratory-scale DD unit operated in a batch configuration to study the effect of process parameters on the efficiency of sulfuric acid recovery. The latter one was a large-scale DD unit operated in a continuous configuration to simulate the process operation at the industrial scale. Results showed that F…
Experimental investigation and modelling for sulphuric acid recovery by diffusion dialysis
2018
Sulphuric acid is known to be one of the key inorganic acid and has been widely used in chemical reaction and metal industries for surface treatments as in the copper electroplating process. During these processes, large amounts of waste sulphuric acid solution are generally generated, containing high concentrations of metals and acid. The possibility of recover and reuse the sulphuric acid in the process could avoid environmental contamination and reduce costs of the disposal. Among several separation methods, diffusion dialysis (DD) is becoming more and more attractive thanks to the recent important advances in ion exchange membranes (IEMs) field and because of its clean nature and operat…