Recovery and characterization of nickel particles by chemical reduction method from wastes generated in electroless industry

Applicability of Nickel-Based Catalytic Systems for Hydrodehalogenation of Recalcitrant Halogenated Aromatic Compounds

“…Even metallic nickel is much cheaper in comparison with platinum metals-based catalysts (actual price about 20,000 USD/t), and for sustainability of HDH methods the recycling of used Ni is required. For this purpose, hydrometallurgical processes would seem to be suitable energy-saving alternatives to the common pyrometallurgical ones [127][128][129][130][131]. Hydrometallurgical processing methods are environmentally friendly due to the low energy requirements, low gas emissions and waste generations and complete recovery of the metals [127].…”

“…They are based mainly on mineral acid leaching (hydrochloric, nitric or sulfuric acid) with appropriate co-action of oxidant (hydrogen peroxide, persulfate, etc.) [127][128][129][130][131][132] (Scheme 26). The obtained re-Scheme 25.…”

“…They are based mainly on mineral acid leaching (hydrochloric, nitric or sulfuric acid) with appropriate co-action of oxidant (hydrogen peroxide, persulfate, etc.) [127][128][129][130][131][132] (Scheme 26). The obtained refined nickel salts such as nickel chloride, nitrate or sulfate are usually used for preparation of Ni-based HDH catalysts and eventually reduced directly to metallic nickel by the action of electropositive metal, NaH 2 PO 2 or NaBH 4 [51,60,63,[128][129][130][131].…”

“…[127][128][129][130][131][132] (Scheme 26). The obtained refined nickel salts such as nickel chloride, nitrate or sulfate are usually used for preparation of Ni-based HDH catalysts and eventually reduced directly to metallic nickel by the action of electropositive metal, NaH 2 PO 2 or NaBH 4 [51,60,63,[128][129][130][131].…”

CaO2/UV Process for One-Step Phosphorus Removal and Recovery from Hypophosphite: Simultaneous Oxidation and Precipitation

“…Given the importance of P recycling, P removal and recovery from waste streams have been widely practiced worldwide. ,− Currently, the most common method for P removal is chemical precipitation or crystallization, in which P is converted from soluble phosphate to insoluble or less soluble P minerals. − However, the existing methods, including chemical precipitation, are ineffective when targeting hypophosphite (H 2 PO 2 – , P at a valence state of +1), which is ubiquitous in some industrial wastewater, i.e., electroless plating industry. , Hypophosphite is heavily used in the electroless nickel plating industry as a reducing agent . It is constantly replenished during the plating process, leading to large amounts of (hypo)­phosphite remaining in the scrapped electroless solution. , Compared with phosphate (PO 4 3– ) minerals, hypophosphite minerals (i.e., calcium hypophosphite) are much more soluble. − Therefore, the direct treatment of hypophosphite by existing phosphate removal and recovery methods is inefficient.…”