Sample inhomogeneity is a severe issue in printed circuit boards especially when we are comparing the bioleaching efficiency. To avoid the ambiguous results obtained due to inhomogeneity in PCBs, 12 similar cell phone chargers (of renowned company) having same make and batch number were collected from scrap market. PCBs obtained from them were used in present studies. Out of these 12, three PCBs were used separately for chemical analysis of PCBs with prior acid digestion in aqua regia. It was found that, 10.8, 68.0, and 710.9 mg/l of Zn, Pb, and Cu were present in it, respectively. Six PCBs were used for bioleaching experiment with two variations, pulverized and non-pulverized. Though the pulverized sample have shown better leaching than non-pulverized one, former has some disadvantages if overall recycling of e-waste (metallic and nonmetallic fraction) is to be addressed. At the end of leaching experiments, copper was recovered using a simple setup of electrodeposition and 92.85% recovery was attained. The acidophiles involved in bioleaching were identified by culture dependent and culture independent techniques such as DGGE and species specific primers in PCR.

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CoCeO2 NPs were successfully synthesized and confirmed using x‐ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and high‐resolution transmission electron microscopy (HRTEM) techniques. The catalytic performance of the synthesized CoCeO2 NPs catalyst was examined during the one‐pot multicomponent synthesis of biologically significant 2‐amino‐3‐cyano‐4H‐pyran derivatives. The reaction was easily accomplished using a one‐pot, three‐component reaction of dimedone, aryl aldehydes, and malononitrile in ethanol under reflux, with excellent yields and a short reaction time. The current catalytic system is more appealing because of its simple reaction conditions, uncomplicated product isolation, economic feasibility, and reusability of the catalyst free from significant loss of activity. This process offers an effective strategy for the synthesis of 2‐amino‐3‐cyano‐4H‐pyran derivatives.

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