Biosensor for heavy metals detection in wastewater: A review.

Pollution due to heavy metals is a global issue in recent years. Initially, there were fewer contaminants, which has increased exponentially owing to rapid industrialization and various anthropogenic activities. Toxicity due to heavy metals causes a lot of health problems and organ system failure in human beings. It also affects other forms of living beings such as plants, animals and even the microbiota. This has been reported by various press reports and research findings. In this review, the production of heavy metals, associated effects on the environment and the technologies employed for detecting these heavy metals are comprehensively discussed. The analytical instruments, including biosensors, have been found to be more beneficial than other techniques. Biosensor exhibits numerous special features, such as reproducibility, reusability, linearity, sensitivity, selectivity, and stability. Over the last three years, biosensors have also had a detection limit of 65.36 ng/mL for heavy metals. The design of biosensors, features and types were also explained in detail. The limit of detection for the heavy metals in wastewater using biosensors was also included with recent references up to the last five years.

Coimmobilized enzymes as versatile biocatalytic tools for biomass valorization and remediation of environmental contaminants - A review.

Due to stringent regulatory norms, waste processing faces confrontations and challenges in adapting technology for effective management through a convenient and economical system. At the global level, attempts are underway to achieve a green and sustainable treatment for the valorization of lignocellulosic biomass as well as organic contaminants in wastewater. Enzymatic treatment in the environmental aspect thrived on being the promising rapid strategy that appeased the aforementioned predicament. On that account, coimmobilization of various enzymes on single support enhances the catalytic activity ensuing operational stability with industrial applications. This review pivoted towards the coimmobilization of enzymes on diverse supports and their applications in biomass conversion to industrial value-added products and removal of contaminants in wastewater. The limelight of this study chronicles the unique breakthroughs in biotechnology for the production of reusable biocatalysts, which inculcating various enzymes towards the scope of environment application.

Surface improved agro-based material for the effective separation of toxic Ni(II) ions from aquatic environment.

In this present study, a novel and low cost surface improved material was prepared from the farm waste material (Borassus flabellifer male inflorescence) and its surface was enhanced by the sulphuric acid treatment to intensify the Ni(II) ions adsorption. The adsorption individualities such as availability of functional groups, essential elements and the exterior side and structural properties of the material were assessed by the FT-IR, EDX, SEM and XRD investigation. The impact of varied adsorption influencing parameters on Ni(II) ions adsorption was studied and optimized as pH - 6.0, biosorbent dosage - 1.5 g/L, contact time - 60 min and temperature - 303 K via batch adsorption examination. Modeling examinations were carried with varied adsorption isotherm (Langmuir, Freundlich, Fritz-Schlunder and Temkin) and kinetic models (Pseudo-first order, Pseudo-second order and Elovich kinetics). Thermodynamic studies were carried out at varied Ni(II) ions concentrations (25 mg/L - 150 mg/L) and temperatures (303 K-333 K) to explain the nature of Ni(II) ions adsorption on Borassus flabellifer male inflorescence. The prepared material has shown the most suitable Ni(II) ions adsorption results for the Langmuir isotherm (R2 = 0.9808) and Pseudo-first order kinetic models (R2 = 0.9735 for 25 mg/L). Thereby, the modeling study revealed that the prepared material has received the Ni(II) ions adsorption capacity (qm) value of 20.31 mg/g and the Ni(II) ions adsorption was physisorption. Thermodynamic results demonstrated that the Ni(II) ions adsorption was immediate, exothermic and favorable at low temperature.