Emerging electrochemical techniques for identifying and removing micro/nanoplastics in urban waters.

Recovery of rare earth by electro-sorption with sodium diphenylamine sulfonate modified activated carbon electrode

Indirect bioleaching recovery of valuable metals from electroplating sludge and optimization of various parameters using response surface methodology (RSM).

A capacitive deionization and electro-oxidation hybrid system for simultaneous removal of heavy metals and organics from wastewater

Abstract Heavy metals are present in wastewater generated by industrial sectors, posing a threat to the environment, including surface and groundwater resources. With this in mind, there is a growing interest in finding alternative yet effective methods of removing heavy metal ions from industrial wastewater. Sorption is one of the techniques being readily applied due to the simplicity, high efficiency, production of small amounts of sludge, low investment, and the feasibility of the process over a wide range of pH and temperature. This paper deals with the treatment of industrial wastewater from electropolishing of stainless steel containing high concentrations of metal ions Fe(III), Cr(III), Ni(II), and Cu(II). Taking into account the effectiveness, availability and applicability of biosorbents for acidic wastewater, orange peels, algae, Eclipta alba , and eggshells were selected for the study. Sorption tests were carried out for Eclipta alba and the results obtained showed a best fit for the second-order kinetic model (R 2 &gt; 0.99) and the Langmuir isotherm model (R 2 &gt; 0.99). Maximum adsorption capacity was 17.92 mg/g for mixture of metal ions. The potential use of dried and calcinated eggshells was established. Both materials achieved a high removal rate of over 95%. Iron and chromium are removed from the solution first (about 100% and 90%, respectively), followed by nickel and copper ions. FT-IR and SEM with EDS measurements used to characterize materials, together with laboratory tests using real industrial effluent, made it possible to determine their mechanism of action. Specific surface area was determined for all tested materials and the values were: 1.63, 0.15 and 5.15 m 2 /g for Eclipta alba , dried eggshells and calcinated eggshells, respectively. The results provide grounds for optimism in the application of selected materials for industrial wastewater treatment. 

/pdf/the-efficiency-of-removing-heavy-metal-ions-from-industrial-bphvh6ow.pdf

The efficiency of removing heavy metal ions from industrial electropolishing wastewater using natural materials

As the world population increases and water resources diminish, the recovery of wastewater has attracted the attention of researchers and government agencies. Besides, the increasing amount of toxic pollutants in groundwater above the threshold raises questions about the efficiency of current wastewater treatments. Nickel-rich wastewater, in particular, has a great contribution to the contamination of water bodies due to its wide application in the electroplating industry, stainless steel manufacturing, and storage battery industries. Its negative consequences are strongly related to human health. Inappropriate selection of metal removal technologies affects aspects of cost, efficiency, and sustainability. Therefore, this review addresses the latest technologies (2017–2021) for treating nickel-rich wastewater. The techniques were divided into four categories: physicochemical, electrochemical, bioremediation, and others. Furthermore, patents and economic aspects were discussed. Consequently, this review sought to offer insights for developing new technologies with lower energy consumption and high removal efficiency, allowing their commercialization. 

Techniques of nickel(II) removal from electroplating industry wastewater: Overview and trends

Electrochemistry aimed at improving the adsorptive capacity of materials has been studied and applied in several industrial fields, such as protein purification, electrocatalysts synthesis, effluent treatment, antibiotic removal and degradation, heavy metals, and waste by-products. Electro-adsorption stands out as an alternative technology to the conventional adsorptive method due to the production of increasingly complex electrodes with better surface properties, porosity, electronic affinity, selectivity, and the ability to perform electrochemical reactions. Other electrochemical processes such as electro-oxidation, electrocoagulation, and electrospinning can be introduced in a concurrent, consequential, or sequential manner for a large-scale process to improve electro-adsorption. The approach allows a lower energy impact during the process by increasing the adsorbent regenerative capacity and increasing the application's stability and cycle number. Most studies present an intrinsic relationship between the working variables with an improvement in the electrochemical adsorption efficiency. The main variables are voltage, current density, pH, and ion concentration in solution. They can be analyzed separately. However, their associated study is more significant in the search for complete answers. In this way, the review presents the main studies, applications, and trends, between 2015 and 2021 regarding electro-adsorption as a technique that aims to replace or improve conventional methods of adsorption, removal, or degradation of compounds.

Recent advances and future applications in electro-adsorption technology: An updated review

The electrodeposition process of metals and their alloys is widely used in the automotive, space, electronics, computing, jewelry, and other consumer items industries. Over the years, the search for new coatings with more suitable characteristics for their application led to the use of ionic liquids (ILs) as electrolytic solutions. In addition to having good conductive properties, the growing interest in these solvents has environmental appeal due to their low toxicity. Furthermore, the ability of these electrolytes to dissolve compounds containing less soluble metals makes them potential substitutes for environmentally harmful solvents. In this sense, this review describes the current state and the innovations concerning the electrodeposition of metals and alloys using ILs as electrolytes in the last five years. Metals were classified into five groups (common, light, noble, rare earth, and others), highlighting not only the ability to form a smooth, homogeneous, and anti-corrosive deposit, but also the reactive capacity of metals in hydrogen evolution and catalytic processes.

/pdf/progress-on-electrodeposition-of-metals-and-alloys-using-2ekflcbt.pdf

Javan Grisente dos Reis da Costa

Papers

Techniques of nickel(II) removal from electroplating industry wastewater: Overview and trends

Recent advances and future applications in electro-adsorption technology: An updated review

Progress on Electrodeposition of Metals and Alloys Using Ionic Liquids as Electrolytes