Phosphate adsorption improvement using a novel adsorbent by CaFe/LDH supported onto CO activated biochar.

It is imperative to remove phosphate from the aquatic system. This nutrient in excess can cause environmental problems such as eutrophication. Therefore, aiming to enhance phosphate removal, this work presents a novel adsorbent developed from the construction of Ca/Fe layer double hydroxides (CaFe/LDH) supported onto biochar physically activated with CO [CaFe/biochar (CO)].

Development of Nylon 6 nanofibers modified with Cyanex-272 for cobalt recovery.

With a worldwide ever increasing demand for metals, particularly for the manufacture of electronics and batteries, there is not only a concurrent need to recover these materials from their subsequent waste streams but also a need to make advancements to do this via development of more efficient and eco-friendly processes for metal recovery; solid-phase extraction can be considered a promising alternative to conventional processes. This work studied the production of novel nanofibers modified with Cyanex 272 and their application in the recovery of cobalt present in aqueous solution The nanofibers produced by forcespinning were characterized by SEM, FT-IR and TGA and the extraction of cobalt was evaluated by variation of the pH, solid:liquid (S:L) ratio, extraction time and Cyanex 272 content in the nanofibers. The best extraction efficiency was 99.

Production of polyacrylonitrile nanofibres modified with Cyanex 272 for recovery of gallium from solution.

The objectives of this work were to develop polyacrylonitrile nanofibres modified with the commercial Cyanex 272 extractor and apply them for the recovery of gallium present in aqueous solution. The nanofibres were produced using the centrifugation technique, employing Forcespinning® equipment. The average nanofibre diameter ranged from 530 to 840 nm.

Evaluation of filter media covered with spun fibres and containing thyme essential oil with antimicrobial properties.

Inhalation of bioaerosols has been linked to many health problems. Filter media impregnated with antimicrobial material can provide effective removal and inactivation of bioaerosols. In this study, fibres were spun on a substrate by centrifugal spinning, obtaining filter media denoted 5THY and THY.

Recovery of copper and aluminium from coaxial cable wastes using comparative mechanical processes analysis.

This work aims to perform a comparative study of two mechanical processes for the recycling of metals from coaxial cables (aluminium and copper-clad steel): Process I - comminution, sieving and electrostatic separation; and Process II - comminution, magnetic separation and electrostatic separation. Characterization techniques were performed on the cables to discover their composition. The parameters evaluated of electrostatic separation were: roll speed (), electrostatic electrode distance (D2), voltage applied to the electrodes () and splitter angle ().

Alternative treatments to improve the potential of rice husk as adsorbent for methylene blue.

Alternative treatments, such as, NaOH, ultrasound assisted (UA) and supercritical CO (SCO), were performed to improve the potential of rice husk as adsorbent to remove methylene blue (MB) from aqueous media. All the treatments improved the surface characteristics of rice husk, exposing its organic fraction and/or providing more adsorption sites. The Langmuir and Hill models were able to explain the MB adsorption for all adsorbents in all studied temperatures.

Adsorption of valuable metals from leachates of mobile phone wastes using biopolymers and activated carbon.

In this work, chitin (CTN), chitosan (CTS) and activated carbon (AC) were used as adsorbents to recover valuable metals from leachates of mobile phone wastes. The mobile phone wastes (contactors) were collected and characterized. The valuable metals were extracted by thiourea leaching.

Comparison between Brazilian agro-wastes and activated carbon as adsorbents to remove Ni(II) from aqueous solutions.

This research was performed to find an alternative, low-cost, competitive, locally available and efficient adsorbent to treat nickel (Ni) containing effluents. For this purpose, several Brazilian agro-wastes like sugarcane bagasse (SCB), passion fruit wastes (PFW), orange peel (OP) and pineapple peel (PP) were compared with an activated carbon (AC). The adsorbents were characterized.

Recovery of cobalt from spent lithium-ion batteries using supercritical carbon dioxide extraction.

Continuing technological development decreases the useful lifetime of electronic equipment, resulting in the generation of waste and the need for new and more efficient recycling processes. The objective of this work is to study the effectiveness of supercritical fluids for the leaching of cobalt contained in lithium-ion batteries (LIBs). For comparative purposes, leaching tests are performed with supercritical CO2 and co-solvents, as well as under conventional conditions.

Recovery of valuable materials from spent NIMH batteries using spouted bed elutriation.

In recent years, a great increase in the generation of spent batteries occurred. Then, efficient recycling ways and correct disposal of hazardous wastes are necessary. An alternative to recover the valuable materials from spent NiMH batteries is the spouted bed elutriation.

Biosorption of gold from computer microprocessor leachate solutions using chitin.

The biosorption of gold from discarded computer microprocessor (DCM) leachate solutions was studied using chitin as a biosorbent. The DCM components were leached with thiourea solutions, and two procedures were tested for recovery of gold from the leachates: (1) biosorption and (2) precipitation followed by biosorption. For each procedure, the biosorption was evaluated considering kinetic, equilibrium, and thermodynamic aspects.

Surface modification of chitin using ultrasound-assisted and supercritical CO2 technologies for cobalt adsorption.

Ultrasound-assisted (UA) and supercritical CO2 technologies (SCO2) were used to modify the chitin surface and, improve its adsorption characteristics regarding to cobalt. Chitin, before and after the treatments, was characterized by N2 adsorption isotherms (BET), infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Unmodified and surface modified chitins were used as adsorbents to remove cobalt from aqueous solutions.