The efficiency of Azadirachta indica (neem leaves) on the removal of Pb(II) ions by adsorption from aqueous solution was investigated in this study. The efficiency of these leaves (without chemical or thermal treatment) for the adsorption of Pb(II) ions has not previously been reported. Batch experiments were performed to study the effect of the particle size, pH, adsorbent dose, contact time, initial Pb(II) ion concentration, and temperature. The maximum removal of 93.5% was achieved from an original Pb(II) ion solution concentration of 50 mg/L after 40 min, at pH 7, with 0.60 g of an adsorbent dose. The maximum adsorption capacity recorded was 39.7 mg/g. The adsorption process was also studied by examining Langmuir, Freundlich, Temkin isotherm, and Dubinin–Radushkevich (D-R) isotherm models. The results revealed that the adsorption system follows the pseudo-second-order model and fitted the Freundlich model. Several thermodynamic factors, namely, the standard free energy (∆G°), enthalpy (∆H°), and entropy (∆S°) changes, were also calculated. The results demonstrated that the adsorption is a spontaneous, physical, and exothermic process. The surface area, pore size, and volume of adsorbent particles were measured and presented using a surface area analyzer (BET); the morphology was scanned and presented with the scanning electron microscope technique (SEM); and the functional groups were investigated using μ-FTIR.
Proper treatment and disposal of industrial pollutants of all kinds are a global issue that presents significant techno-economical challenges. The presence of pollutants such as heavy metal ions (HMIs) and organic dyes (ODs) in wastewater is considered a significant problem owing to their carcinogenic and toxic nature. Additionally, industrial gaseous pollutants (GPs) are considered to be harmful to human health and may cause various environmental issues such as global warming, acid rain, smog and air pollution, etc. Conductive polymer-based nanomaterials have gained significant interest in recent years, compared with ceramics and metal-based nanomaterials. The objective of this review is to provide detailed insights into different conductive polymers (CPs) and their nanocomposites that are used as adsorbents for environmental remediation applications. The dominant types of CPs that are being used as adsorbent materials include polyaniline (PANI), polypyrrole (Ppy), and polythiophene (PTh). The various adsorption mechanisms proposed for the removal of ODs, HMIs, and other GPs by the different CPs are presented, together with their maximum adsorption capacities, experimental conditions, adsorption, and kinetic models reported.
The rising level of atmospheric carbon dioxide (CO2) is a major driver of climate change, highlighting the need to develop carbon capture and storage (CCS) technologies quickly. This paper offers a comparative review of three main groups of porous adsorbent materials—zeolites, metal–organic frameworks (MOFs), and activated carbons—for their roles in CO2 capture and long-term storage. By examining their structural features, adsorption capacities, moisture stability, and economic viability, the strengths and weaknesses of each material are assessed. Additionally, five different methods for delivering these materials into depleted oil and gas reservoirs are discussed: direct suspension injection, polymer-assisted transport, foam-assisted delivery, encapsulation with controlled release, and preformed particle gels. The potential of hybrid systems, such as MOF–carbon composites and polymer-functionalized materials, is also examined for improved selectivity and durability in underground environments. This research aims to connect materials science with subsurface engineering, helping guide the selection and use of adsorbent materials in real-world CCS applications. The findings support the optimization of CCS deployment and contribute to broader climate change efforts and the goal of achieving net-zero emissions. Key findings include CO2 adsorption capacities of 3.5–8.0 mmol/g and surface areas up to 7000 m2/g, with MOFs demonstrating the highest uptake and activated carbons offering cost-effective performance.
12 January 2023 in Journal of the Taiwan Institute of Chemical Engineers
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Unconventional reservoirs, including gas shales and tight gas sands, have gained prominence in the energy sector due to technological advancements and escalating energy demands. The oil industry is eagerly refining techniques to decipher these reservoirs, aiming to reduce data collection costs and uncertainties in reserve estimations. Characteristically, tight reservoirs exhibit low matrix porosity and ultra-low permeability, necessitating artificial stimulation for enhanced production. The efficacy of the stimulation hinges on the organic material distribution, the rock’s mechanical attributes, and the prevailing stress field. Comprehensive petrophysical analysis, integrating standard and specialized logs, core analyses, and dynamic data, is pivotal for a nuanced understanding of these reservoirs. This ensures a reduction in prediction uncertainties, with parameters like shale volume, porosity, and permeability being vital. This article delves into an intricate petrophysical evaluation of the Nene field, a West African unconventional reservoir. It underscores the geological intricacies of the field, the pivotal role of data acquisition, and introduces avant-garde methodologies for depth matching, rock typing, and the estimation of permeability. This research highlights the significance of unconventional reservoir exploration in today’s energy milieu, offering a granular understanding of the Nene field’s geological challenges and proffering a blueprint for analogous future endeavours in unconventional reservoirs.