Indian Journal of Chemical Technology (IJCT)

Advances in biochar-based absorbents: Sustainable solutions for heavy metal removal from contaminated water

2025-03-03T12:46:29+0530

Heavy metal contamination in water poses serious environmental and health risks, necessitating cost-effective and sustainable remediation methods. Biochar, a carbon-rich material produced through the pyrolysis of organic waste such as agricultural residues, sewage sludge, and marine algae, has emerged as an efficient adsorbent for removing heavy metals. This review examines recent advancements in biochar-based adsorption, focusing on key factors influencing its efficiency, including feedstock type, pyrolysis conditions, surface functionality, and porosity. The study explores the role of modified biochars, such as magnetic biochar, in enhancing metal recovery while maintaining high adsorption capacity. The adsorption mechanisms like cation exchange, electrostatic interactions, complexation, and precipitation are analysed to explain the effectiveness of biochar in capturing heavy metals such as Pb(II), Cd(II), Cu(II), and Zn(II). Additionally, the impact of parameters such as pH, contact time, and initial metal concentration on adsorption performance is discussed. While biochar presents a scalable and eco-friendly wastewater treatment solution, challenges such as competitive adsorption in multi-metal systems, regeneration efficiency, and production costs remain. Future research should focus on optimising biochar modifications, integrating it with existing treatment technologies, and enhancing its selectivity for specific contaminants.

Efficacy of hazardous congo red removal from aqueous solutions via adsorption with carbon black: Batch and column study insights

2025-08-12T14:30:49+0530

This study investigates the potential of commercial carbon black, sourced from a local waste tyre recycling plant, as an adsorbent in both batch and continuous column adsorption processes for the removal of Congo red (CR). The carbon black has been characterized using Fourier transform infrared spectroscopy and scanning electron microscopy to assess its surface properties. Additionally, the study aims to analyze the physicochemical interactions between carbon black and CR. Key experimental variables, including adsorbent dosage, pH, and contact time, are optimized through batch adsorption experiments to determine their impact on the removal efficiency of CR dye. Batch adsorption experiments confirmed that carbon black (adsorbent) attains maximum adsorption capacities of 76.92 mg/g for CR dye. Among the tested kinetic models, the pseudo-second-order model (R² = 0.998) best described CR adsorption onto carbon black, outperforming the pseudo-first-order model (R² = 0.986). A Continuous adsorption study has been done to determine the effect of the flow rate of water, adsorbent bed diameter and bed height on the breakthrough time. About 90% removal of CR occurs when the bed height is larger than 5 cm and the bed diameter is larger than 2.7 cm.

Pyrolysis-derived algal oil: A sustainable and high-performance green bio-lubricant

2025-06-17T15:19:06+0530

Lubricating oils are essential in the mechanical industry, but their petroleum-based origin raises increasing environmental concerns. Bio-based lubricants offer a potential solution, provided they can achieve comparable performance and cost-competitiveness with conventional mineral-based and synthetic lubricants. Therefore, this study investigated the performance, biodegradability, and toxicity of pyrolysis-derived algal oil as a sustainable and environmentally friendly alternative to traditional lubricating oils. The pyrolytic algal-based lubricating oil exhibited a flash point of 273°C, indicating a reduced fire hazard, and a pour point of -15°C, suggesting suitability for low-temperature applications. The key advantages of this algal lubricating oil are its high biodegradability and low toxicity. It also demonstrated 85% degradation within 28 days. Toxicity levels have been assessed using both aquatic organisms and soil microbes. This algal lubricating oil is found to have low toxicity, with LC₅₀ values of 125 mg/L for Daphnia magna and 150 mg/L for Danio rerio. Furthermore, the results showed that this algal lubricating oil enhanced soil microbial activity by 10%. The impact on plant life was assessed by monitoring germination and growth. A 90% germination rate is recorded, and subsequent plant growth is positive, with an observed biomass increase of up to 85%. Spill recovery tests demonstrated high recovery efficiencies of 85% in water and 80% in soil. The findings of this study support the use of pyrolysis-derived algal oil as a sustainable alternative to traditional lubricants.

Cattaneo-Christov heat flow analysis of hydromagnetic micropolar nanofluid over a chemically activated permeable stretching sheet

2025-03-24T10:45:03+0530

Several engineering and technological processes, such as air conditioning, machinery power collectors, food processing, refrigeration, and heat exchangers, need deep investigation of energy and mass transfer in various conditions. As a result, in this paper, we analyze the radiative flow of a hydromagnetic micropolar nanofluid with activation energy and chemical reaction using the Cattaneo-Christov energy flux model over an expanding porous sheet. Further, the consequences of suction, energy generation, and convective boundary conditions were also examined. Boundary layer approximation is utilized to obtain the primary partial differential equations of the model and reduced to nonlinear ordinary differential equations, using the appropriate transformations, the model equations are formulated for numerical simulation and further analysis. Using the inbuilt BVP5C function available in MATLAB, the numerical solutions for the coupled system of the nonlinear ordinary differential equations are obtained. Further, graphical and tabular representations are used to analyze the impacts of several physical parameters on the concentration, velocity, temperature, and microrotation fields. The outcomes reveal that the velocity and microrotation of the micropolar liquid movement are improved by increasing the magnetic and material parameters. An increase in the concentration Grashof number, thermal relaxation parameter, and temperature Grashof number leads to a reduction in the temperature distribution within the thermal boundary layer. Furthermore, the mass transfer rate is directly proportional to the thermophoresis and chemical reaction parameters.

A novel spectrophotometric three point detection method for estimation of montelukast sodium and bilastine individually as well as simultaneously in bulk drug, aqueous samples and formulations

2025-06-03T14:41:38+0530

Montelukast sodium and bilastine have been approved in fixed dose combination of 10 mg and 20 mg, respectively, by CDSCO for treatment of allergic rhinitis in adults. Quantitative estimation of drugs is of vital importance during various stages of drug development. Simultaneous estimation of such drugs is a concern as these interact with each other during estimation. Bilastine was not found to interact montelukast sodium at its absorption maximum i.e. 344 nm whereas montelukast sodium was found to interact bilastine throughout UV range. So, montelukast sodium has been simply evaluated at 344 nm as single standard while developing a novel method for estimation of bilastine simultaneously nullifying the interaction of montelukast sodium. The calibration graphs for montelukast sodium and bilastine are linear over concentration ranges of 6-40 μg/mL and 4-40 μg/mL, respectively. As per ICH Q2 (R1) guidelines, both the curves have been found to be specific, precise, accurate, robust and rugged as indicated by the results of validation parameters within specified limits. Also, the method neither requires any complex equipment nor specific software. The calibration curves, thus formed, are useful to evaluate the respective drug alone and in the mixtures/ samples of these two drugs in combination.

Production of renewable fuels and chemicals by combining hydrothermal pretreatment with thermochemical conversion of woody biomass towards solid waste management

2025-02-06T14:34:35+0530

Finding an ecologically and economically viable technique of processing biomass to produce biofuel is a vital one. Upgrading biomass for thermochemical processes using high temperature water (HTW) treatment is discussed in this study. In the present investigation, Ficus religiosa biomass is pretreated with HTW and pyrolyzed at temperature ranges from 350 °C to 550 °C. A fixed bed pyrolysis system is employed to convert raw biomass into valuable liquid and solid products. The liquid oil and char obtained through the pyrolysis process are characterized using different physical analysis. The chromatographic technique of gas chromatography mass spectroscopy (GC-MS) is also employed for the analysis of end products. The HTW treatment has been found to stimulate the synthesis of high energy value char and boost the product yield. The pretreatment is also more effective towards the production of aliphatic compounds.

Cu-Doped chicken eggshells: An eco-friendly catalyst for the production of green biodiesel with Azadirachta indica seed oil to promote the circular economy

2024-12-24T12:08:32+0530

In this study, waste eggshell (WES) has been used to manufacture a heterogeneous Cu-CaO catalyst and used for Azadirachta indica seed oil straight transesterification. The catalyst is made via wet impregnation, which produced a crystalline structure having an area on the surface of 4.8893 m²/g and on average, the size of the pores 275.826 Å, as measured by XRD and BET measurements. The composition of the Cu-CaO catalyst is further verified by SEM-EDS analysis. The direct transesterification process has been optimized by modifying the catalyst dosage (%), reaction temperature (°C), ethanol mole ratio, and time (min). At a catalyst quantity of 9% wt/wt, 3 h response duration, 12:1 Ethanol to oil mole proportion, and 65°C temperature, the maximum yield of Methyl Ester of Fatty Acid (90%) is obtained. In addition, a number of characteristics of the produced biodiesel are measured, including cloud point 9°C, pour point 4°C, higher heating value 38.86 MJ/kg, acid value 0.32 mg KOH/g, density 0.8553 g/cm³, kinematic viscosity 5.10 cSt, and moisture content 0.03. After six cycles, the Cu-CaO catalyst's stability and reusability are established. These results show that eggshell waste-derived Cu-CaO catalyst has the potential to be an affordable, sustainable and environmentally friendly catalyst for the synthesis of biodiesel.

Synthesis of ternary nanofluids and optimization of their thermophysical properties using artificial neural network

2024-12-10T14:45:24+0530

This work focuses primarily on the two-step synthesis of ternary nanofluids consisting of silver (Ag), graphene oxide (GO), and multi-walled carbon nanotubes (MWCNT) in volume fractions ranging from 0.005 to 0.03, their stability and structural (morphological) analysis, and appraisal of their thermophysical properties such as thermal conductivity, viscosity, density and specific heat capacity in the temperature range from 20 to 80°C. The thermal conductivity and viscosity were found to be 0.7845 W/m.K and 0.8718 cP at 30°C for 3 vol %. The work also involved the optimization and validation of these thermophysical parameters using Artificial Neural Network (ANN). The ANN was constituted and tested with the application of Levenberg-Marquardt (LM) algorithm. The titular network size has been inherently optimized as per the relative error to enhance the model’s ability to predict thermal conductivity and viscosity. The Levenberg-Marquardt feed-forward network possessing the optimal network design, 6 – 1 (hidden layer nodes – Output layer nodes) for thermal conductivity and 2 – 4 for viscosity have been identified as the best training approach. The ANN results exhibit the coefficient of regression (R²) to be significant at 0.99736 and 0.99725 for thermal conductivity and viscosity respectively, and the upper limit of relative error was negligible. The same data set subjected to the standard fitting model gave the R² of 0.9931 and 0.9944 with mean square error of 0.0064 and 0.0170, respectively.

Photocatalytic degradation of bisphenol a using hybrid oxalate-pyrite/chitosan

2024-11-18T14:12:39+0530

This study investigated the photocatalytic degradation of Bisphenol A (BPA) using a low-cost and environmentally friendly hybrid catalyst composed of oxalate-pyrite/chitosan. The effects of initial BPA concentration, catalyst dosage, and pH on the percentage of BPA degradation are examined. Additionally, both adsorption and photocatalytic degradation kinetics are evaluated. The findings revealed that BPA degradation is most effective at a lower initial concentration (5 mg/L) and at neutral pH (pH 7). Moreover, increasing the catalyst dosage led to a rise in photodegradation efficiency, although the improvement is not significant. The adsorption of BPA onto the hybrid oxalate-pyrite/chitosan catalyst conformed to the pseudo-second-order kinetic model, while the photocatalytic degradation followed pseudo-first-order reaction kinetics.

Cycas inermis plant leaves extract as an environmental-friendly corrosion inhibitor extracted by efficient Soxhlet extraction technique for soft cast steel in 1 MH2SO4

2024-12-03T15:09:39+0530

Plant extracts as corrosion inhibitors have received significant attention due to their potential activities and cost-effectiveness. In this current work, it is intended to utilize the inhibitive activity of the Cycas inermis plant leaves extract (CILE) to mitigate the corrosion of soft cast steel (SCS) in sulfuric acid medium and reduce the environmental risk. The studies revealed that the inhibition efficiency of CILE increases with higher concentrations of the inhibitor but decreases with rising temperatures. The maximum inhibition efficiency of 96.15% has been achieved at a concentration of 2.0 g/L. The adsorption of CILE on the SCS surface follows the Langmuir adsorption isotherm model. Surface morphology analyses of both uninhibited and inhibited SCS have been evaluated using scanning electron microscopy (SEM), atomic force microscopy (AFM), and water contact angle (WCA) measurements. SEM analysis indicated that the metal surface is significantly protected from aggressive corrosion due to the inhibitor. AFM visualization confirms the formation of a protective layer on the steel surface, which resulted in a reduction in surface roughness. Overall, this study demonstrates the potential of CILE as an effective, environmentally friendly corrosion inhibitor for soft cast steel in acidic environments.

Reaction optimization of biodiesel production from synthesized W/K/CaO catalyst using food waste: A sustainable waste to energy solution

2024-12-04T13:18:39+0530

The advancement of using food waste for energy conversion has attracted considerable attention among researchers. The present study investigates the sustainable way of biodiesel production using food waste as a green and innovative solution that aids in both the preservation of the environment and the efficiency of resource utilization. In this work, the sodium salt of tungstic acid and K⁺ were coated over eggshells-derived CaO to convert the waste cooking oil (WCO) to biodiesel. The synthesized catalyst has been subjected to various characterization techinques such as XRD, FT-IR and SEM-EDX analysis. Response surface methodology approach is used to optimize the important parameters of transesterification reaction. The optimized conditions to transesterify waste cooking oil with synthesized W/K/CaO is found to be of 4 wt% of synthesized W/K/CaO catalyst, 13.7:1 ratio of methanol: oil, 90 min reaction duration and 60℃ reaction temperature. The maximum biodiesel yield of 98.04% was obtained using the optimized conditions. Gas chromatography-mass spectroscopy (GC-MS) analysis and NMR studies were used to characterize the produced biodiesel. Finally, the reusability of the catalyst has also been discussed.

Comparison of rCCD and BBD design for reactive separation of gallic acid using trioctylamine in lauryl alcohol

2024-12-04T13:50:06+0530

Rotatable Central Composite Designs (rCCD) and Box–Behnken Design (BBD) have been used as statistical multivariate methods in the optimization of reactive separation of gallic acid from the aqueous solutions using trioctylamine as extractant dissolved in lauryl alcohol. Effects of variable such as initial concentration of gallic acid (0.02- 0.04 kmol.m^-3), extractant (20–40%, v/v in diluent), temperature (298-318 K) on the separation efficiency of gallic acid have been investigated. rCCD model predicted the maximum separation efficiency of 84.54% at the conditions of initial acid concentration (0.031 kmol.m^-3), extractant volume percentage (17.20 % v/v in diluent ) and temperature (298 K) as the optimal solution. BBD model suggested that the optimum conditions are initial acid concentration (0.031 kmol.m^-3), extractant volume percentage (17.82 %v/v in diluent) and temperature (298.68 K) provided separation efficiency of 83.71%. The exactness of the two models is judged based on the actual experiments at some random points. Results indicate that the rCCD and BBD are both are reasonably accurate with rCCD slightly more accurate as shown by lower residual square error obtained using the values predicted by both the models.

2025-09-27T09:35:29+0530

CSIR-NIScPR

Author Index & Keyword Index

2025-09-27T09:40:49+0530