Indrashis Saha

Bio: Indrashis Saha is an academic researcher from University of Calcutta. The author has contributed to research in topics: Composite material & Acoustic emission. The author has an hindex of 1, co-authored 4 publications receiving 2 citations.

Sorbents from waste materials: A circular economic approach

Abstract: Contaminants emerging from increasing anthropogenic activities are leading to environmental pollution that has profound effect on the ecosystem and human health. In recent years, new water pollutants have become source of significant concern. Traditional methods for wastewater treatment are inefficient and expensive to tackle such emerging contaminants. Alternative, inexpensive and novel techniques are imperative for wastewater treatment with higher efficiency. Adsorption is the most cost-effective technology for water treatment and hence has been applied widely as a low cost, competent, and eco-friendly method for wastewater treatment. Although water pollution is a big issue, another catastrophic problem on the anthropogenosphere is the management of solid waste. There are several examples where waste resources have been used as precursor for development of sorbent materials having wide range of applications. The resultant sorbents also vary in their structure and properties as some of them are classified as nanomaterials as well. The types of waste used as precursor vary widely such as industrial waste, biomass, polymer waste, and even electronic waste. Although the majority of the applications are focused on primarily on wastewater treatment, some of the reported literature has focused on other environmental hazards such as oil spillage, gas upgradation, and CO2 capture. This is an interesting approach where the end product of one anthropogenic activity is being modified for remediation of another anthropogenic activity. This is a perfect case where the loop further can be closed giving rise to a circular economic approach. This study provides a summary of sorbent materials manufactured from waste materials with their different applications. A novel circular economy framework has been proposed based on the outcome of the literature review. This study is anticipated to be helpful for researchers, policy-makers, governing bodies, and relevant stakeholders.

Modeling, simulation, and characterization of spinning basket membrane module in recovery of proteins from synthetic wastewater

Abstract: Membrane-based low-cost recovery of nutritional and therapeutic proteins from wastewater is regarded as a leap towards sustainability. However, membranes are heavily fouled by proteins, and thus, frequent chemical or hydrodynamic cleaning is needed even in the advanced dynamic shear-enhanced (DSE) filtration devices. This article presents the modeling, simulation, and characterization studies of a DSE system, namely the ‘Spinning Basket membrane’ (SBM) module with an inbuilt cleaning facility. The device has been established to be specifically suitable for the recovery of proteins from synthetic wastewater. It can perpetually regenerate the flux with its simple and, moreover, online cleaning facility. A two-parameter transient model, purely based on an analytical approach, has been developed to simulate the device. Moderately low deviation (±12 %) of the simulated flux from the corresponding experimental data obtained from ultrafiltration of synthetic wastewater unambiguously validates the proposed model. The present modeling strategy demonstrates how a DSE filtration system with highly complex modes of mass and momentum transfer could be easily simulated.

Aerodynamic Study of an Ahmed Body with the Help of CFD Simulation

Abstract: Indrashis Saha, Tathagatha Mukherjee, Ankit Saha, Richa Pandey a) indrashissaha98@gmail.com, b) tatha95@gmail.com, c) ankit18saha@gmail.com, d) richapandey@bitmesra.ac.in 1,3. Department of Chemical Engineering, University of Calcutta, India Department of Mechanical Engineering, Birla Institute of Technology, Mesra, India Assistant Professor, Department of Mechanical Engineering, Birla Institute of Technology, Mesra, India

Resource Resurgence from COVID-19 Waste via Pyrolysis: a Circular Economy Approach

Abstract: Since the end of 2019, COVID-19 pandemic has affected 220 countries and currently majority of the world is facing the wrath of the second wave. One of the outcomes of the ongoing pandemic is the generation of huge amount of solid polymeric “COVID-waste” comprising medical waste, personal protective equipment (PPE) waste, packaging waste, and other household waste with potential infectious components residing on it. Thermochemical route is the preferred treatment and effective way of disposal of such infectious polymeric waste. Typically, incineration is employed to ensure complete destruction of the pathogens which is not a resource-efficient method. Pyrolysis is a sustainable alternative which can handle the present COVID-waste stream in short-term and long-term yielding valuable fuel and material products. Recently published literature in this avenue have clearly shown the versatility of this technology in efficiently handling both mono and mixed stream of polymers. Based on facts, we propose a resource resurgence framework that utilizes pyrolysis as the core conversion route for effectively handling COVID-waste streams. Our framework suggests how these plants can be operational and helpful in generation of revenue in post-pandemic times as well. We expect that the conscientious adoption of pyrolysis will certainly lead us towards a circular economy paradigm.

Application of turbulence promoter in protein recovery from food wastewater by dynamic shear enhanced ultrafiltration

Abstract: The expected growth of membrane technology in protein recovery from wastewater is largely impeded by operational non-idealities like concentration polarization and membrane fouling. Two independent concepts, namely, the Dynamic Shear Enhanced (DSE) filtration and turbulence promoters were introduced decades earlier to remediate the problems. However, no systematic effort was undertaken to explore the synergy of the two process intensification schemes. In this study, we have investigated the effects of simple wire-type turbulence promoter on a specific class of DSE membrane modules, the spinning basket filtration units. The maximum flux improvement with synthetic wastewater (i.e., Bovine Serum Albumin (BSA)-water solution) was 445%, whereas for the real dairy effluent, the respective enhancement levelled off at 204%. The lower level of flux enhancement for real wastewater may be attributed to the severe fouling caused by the casein micelle. The increase of power consumption in all promoter-fitted configurations was limited to 9% only. Thus, turbulence promoter-integrated spinning basket group of membrane modules are confirmed to be much superior relative to other devices in protein recovery from wastewater. Our results are also supported by corroborating computational fluid dynamic (CFD) simulations of elevated shear and high turbulent kinetic energy dissipation rates for all promoter-fitted configurations. The present outcomes clearly recommend the application of turbulence promoters in DSE modules to maximally increase the protein recovery from wastewater even at concentrations where the standard cross-flow systems are apprehended to be non-functional.

Silica-functionalized pyrite core-shell particle as a new mesoporous adsorbent for water-soluble dyestuffs: Characterization, kinetic and thermodynamic studies

Abstract: Environmental problems caused by non-economic minerals in mining processes are among the most significant mining activity challenges. Pyrite is the most abundant sulfide and waste mineral due to acid mine drainage and polluting the environment. The project aims are to synthesize a mesoporous silica-based coating on the surface of natural pyrite (Pyrite@Silica) to prevent oxidation and production of acidic effluent and evaluate its efficiency as an adsorbent for cationic dyes, such as malachite green oxalate (MG) and methylene blue (MB). The study’s strength is that Pyrite@Silica demonstrated a significant adsorption capability in comparison to other natural adsorbents. Pyrite@Silica was prepared during the sol-gel process using tetraethyl orthosilicate (TEOS). In this study, the chemical, mineralogical and morphological characteristics of activated pyrite and Pyrite@Silica were characterized by XRD, XRF, FT-IR, SEM, EDX, TEM, and BET analysis. The optimum conditions of MG and MB adsorption were recorded to be contact time 10 min, Pyrite@Silica dose 3 g.L-1, initial concentration 600 mg.L-1 for malachite green and 200 mg.L-1 for methylene blue at pH 8. The maximum adsorption capacity for MG and MB adsorption dyes at 298 K was obtained 349 mg.g-1 and 97 mg.g-1, respectively. Equilibrium and thermodynamic studies indicated that the adsorption process is a heterogeneous, endothermic, chemical and non-spontaneous. Kinetic studies revealed that both adsorbent and adsorbate effectively affect the adsorption mechanism and also the diffusion mass transfer coefficient is higher than the film mass transfer, which indicates that the resistance of mass transfer is not dependent on the film mass transfer.

Analogy of scaling law for heterogeneous interfacial fracture to explain the Gutenberg–Richter formula for earthquakes

Abstract: We propose a new approach for the statistical law due to the fracture of a heterogeneous interface involving spatial correlation of disorders. The dynamic process of interfacial fracture is governed by three coupled integral equations, which further become a system of linear algebraic equations after discretizing the interface to a set of prismatic elements. By tuning parameters, this model covers the whole cases of interfacial fracture from local-load-sharing to almost equal-load-sharing, extending the classical fiber bundle models to a general form. Numerical simulations present that in all cases, the statistical frequency distribution of bursts follows a power law with the exponent in the range (1.5, 2.5), the corresponding b-value in (0.75, 2.25), which well explains the empirical Gutenberg–Richter scaling. The exponent depends on stiffness of elastic spaces, heterogeneous properties of interface, and the distribution of displacements induced by loading. Furthermore, the exponent drops temporally with the evolution of fracture, to its final value before rupture of interface, a phenomenon that may be treated as a precursor for imminent catastrophic failure.