Research Experience

Ti|PbO2|Graphene oxide electrode (2022)

Although the PbO2 electrode shows good conductivity and stability, it has a small surface area and low catalytic activity that are both effective in degradation and electrowinning. In this research, we improved the surface area and low catalytic activity of the PbO2 electrode with graphene oxide. Pulse current and direct current techniques were utilized. The concentration of GO were 0.2, 0.05, and 0.025 g/l. Electrodeposition was performed in the following conditions: Pb2+ concentration of 0.2 M, temperature of 60°Ϲ, pH of 3-4, 30 minutes of each current density of 50, 30, 20 mA⋅cm−2 for pulse technique, 10 minutes of each step for direct current density, duty cycle of 30%, and frequency of 50 Hz.

OCP, EIS, and CV tests were applied to examine the electrochemical characterization of electrodes. The results illustrate that graphene increased the electrocatalytic activity. CV, EIS, and the accelerated lifetime test suggest that the PbO2|GO(0.05g/l) has optimal electrocatalytic activity and stability. Also, the pulse current technique showed much better performance rather than the direct current.

Ti|PbO2|GO(0.05 g/l)

Electrodeposition of PbO2|GO(0.05 g/l)

Using two pieces of graphite for electrochemical synthesis of graphene

Electrochemical Synthesis of Graphene oxide (2022)

Recently, graphene oxide has intrigued a lot of attention due to its fantastic properties. One of our research group activities is to investigate the effect of graphene oxide on electrowinning or degradation anodes. Therefore, we were searching for a simple and practical way to synthesize graphene oxide. The electrochemical synthesis of graphene showed excellent potential to answer our needs.

Two pieces of graphite were used as cathode and anode in 0.5M nitric acid. First, for 30 seconds, 10V was applied, and then the anode and cathode were switched. In this condition, a voltage from 0 to 10, step by step, increased. Each step increased by 0.5V and lasted for 3 minutes.

Recovery of zinc and cadmium from the cold-purification filter cake using glycine as the lixiviant (2022)- In preparation

This work presents a novel leaching reagent for the recovery of elements from cold-purification filter cake of zinc. Cold-purification filter cake of zinc is a by-product generated during zinc production by hydrometallurgy. The currently designed route uses glycine as an environment-friendly lixiviant, which makes a fast dissolution.

In this research, the effect of temperature, pH, leaching time, glycine concentration, and L/S was examined. It was found that more than 96.4% of zinc and 92.2% of cadmium could be leached under the following conditions: glycine concentration of 2M, temperature of 70°Ϲ, time of 3 hours, L/S of 20:1, pH of 10.

leaching solution of cold cake, warm cake, and mix of them by glycine

leaching solution of LIB batteries in pH of 7-11 by glycine

microwave leaching

Microwave-assisted selective leaching of valuable metals from spent lithium-ion batteries using glycine lixiviant system (2022-Bachelor thesis)- In preparation

The future shortage of elements used in the batteries' cathode caused concerns in many industries, and one promising solution is recycling. In this work, an environment-friendly lixiviant, glycine, was utilized to recover cobalt and lithium from nickel and manganese selectively. Two leaching steps were presented. First, the leaching of nickel and manganese by glycine in the microwave. Secondly, the conventional leaching of lithium and cobalt by oxalic acid. As a result, cobalt precipitated as cobalt oxalate.

In the first step, nickel and manganese were recovered 93.3% and 96.7%, respectively, while only 7.5% of cobalt and 4.1% of lithium were leached in the following conditions: microwave power of 500W, 15 minutes, 0.01M ascorbic acid, glycine concentration of 3M, L/S of 20:1, pH of 9. Also, it was found that glycine can recover more than 95% of cobalt by adding ascorbic acid to 0.1M in the microwave.

In the second step, lithium and cobalt were ideally recovered from the residue of the first step. The recovery rate for cobalt and lithium were 95.7% and 98.1%, respectively. The conditions of this step were as follows: temperature of 80°Ϲ, time of 3 hours, oxalic acid concentration of 1M, and L/S of 20:1.

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