Sorption of nickel and cadmium ions from aqueous solutions by a complexing resin based on modified polyamide fiber

Abstract

The sorption of nickel and cadmium ions by a fibrous complexing resin containing functionally active amines was studied. The principal kinetic and concentration characteristics of the processes and the coordination properties of the resulting complexes were determined.Sorption technologies play an important role in solving ecological problems, in particular, purification of wastewater and atmospheric releases. Polymeric sorbents in the form of ion-exchange resins and chemically absorptive fibers have been used the most in these processes [1,2]. It is noteworthy that fibrous sorbents have several advantages over granular ion-exchange resins despite their lower capacities. The kinetic parameters of the sorption and desorption processes are greater owing to a more developed specific surface area. The apparatus configuration for the sorption processes can be widely varied because of the variety of shapes of the fibrous material. The resistance to breathing in respirators is reduced significantly if a fibrous filtering element is used. They are mechanically stronger.The problem of extracting and concentrating heavy metals, in particular, from wastewaters of electrochemical and etching manufacturing, has recently become especially important both ecologically and economically. The discharge of wastewaters after plating chromium and zinc; passivation; plating cadmium, nickel, and copper; and etching causes irreparable damage to the ecology and also economic losses due to the loss of pure water and valuable chemicals.Heavy metals (nickel, cadmium, lead, chromium, etc.) are some of the most dangerous contaminants. Their compounds are highly toxic and capable of accumulating in various components of the ecosystem, including in living organisms. In contrast with other chemical components in the composition of natural waters, they do not decompose but only change speciation as the physicochemical conditions of the medium change.The most common methods at present for purifying wastewaters use reagents, membranes, electrochemistry, and flotation. They do not provide purification of wastewaters over a broad concentration range to the maximum allowable concentration (MAC) and maximum allowable release (MAR). Methods based on combinations, e.g., of reagent and chemical sorption methods (by ion-exchange and complexation mechanisms), are most promising [3,4].

Separation of Ni(II) and Cd(II) Ions with Supported Liquid Membranes (SLM) using D2EHPA as a Carrier

“…In recent years, ion-exchange has received interest as one of the most promising methods to purify wastewaters laden with heavy metals (7)(8)(9). Another technology which can play an important role in solving ecological problems caused by heavy metals is sorption (7,10). A special form of sorption is biosorption.…”