Due to rapid industrialization and urban development across the globe, the emission of carbon dioxide (CO₂) has been significantly increased, resulting in adverse effects on the climate and ecosystems. In this regard, carbon capture and storage (CCS) is considered to be a promising technology in reducing atmospheric CO₂ concentration. Among the CO₂ capture technologies, adsorption has grabbed significant attention owing to its advantageous characteristics discovered in recent years. Porous carbon-based materials have emerged as one of the most versatile CO₂ adsorbents. Numerous research activities have been conducted by synthesizing carbon-based adsorbents using different precursors to investigate their performances towards CCS. Additionally, amine-functionalized carbon-based adsorbents have exhibited remarkable potential for selective capturing of CO₂ in the presence of other gases and humidity conditions. The present review describes the CO₂ emission sources, health, and environmental impacts of CO₂ towards the human beings, options for CCS, and different CO₂ separation technologies. Apart from the above, different synthesis routes of carbon-based adsorbents using various precursors have been elucidated. The CO₂ adsorption selectivity, capacity, and reusability of the current and applied carbon materials have also been summarized. Furthermore, the critical factors controlling the adsorption performance (e.g., the effect of textural and functional properties) are comprehensively discussed. Finally, the current challenges and future research directions have also been summarized.

Starch is one of the most common biodegradable polymers found in nature, and it is widely utilized in the food and beverage, bioplastic industry, paper industry, textile, and biofuel industries. Starch has received significant attention due to its environmental benignity, easy fabrication, relative abundance, non-toxicity, and biodegradability. However, native starch cannot be directly used due to its poor thermo-mechanical properties and higher water absorptivity. Therefore, native starch needs to be modified before its use. Major starch modification techniques include genetic, enzymatic, physical, and chemical. Among those, chemical modification techniques are widely employed in industries. This review presents comprehensive coverage of chemical starch modification techniques and genetic, enzymatic, and physical methods developed over the past few years. In addition, the current applications of chemically modified starch in the fields of packaging, adhesives, pharmaceuticals, agriculture, superabsorbent and wastewater treatment have also been discussed.

The health and environmental concerns of the usage of non-biodegradable plastics have driven efforts to explore replacing them with renewable polymers. Although starch is a vital renewable polymer, poor water resistivity and thermo-mechanical properties have limited its applications. Recently, starch/synthetic biodegradable polymer blends have captured greater attention to replace inert plastic materials; the question of ‘immiscibility’ arises during the blend preparation due to the mixing of hydrophilic starch with hydrophobic polymers. The immiscibility issue between starch and synthetic polymers impacts the water absorption, thermo-mechanical properties, and chemical stability demanded by various engineering applications. Numerous studies have been carried out to eliminate the immiscibility issues of the different components in the polymer blends while enhancing the thermo-mechanical properties. Incorporating compatibilizers into the blend mixtures has significantly reduced the particle sizes of the dispersed phase while improving the interfacial adhesion between the starch and synthetic biodegradable polymer, leading to fine and homogeneous structures. Thus, Significant improvements in thermo-mechanical and barrier properties and water resistance can be observed in the compatibilized blends. This review provides an extensive discussion on the compatibilization processes of starch and petroleum-based polymer blends.

As the primary greenhouse gas, CO₂ emission has noticeably increased over the past decades resulting in global warming and climate change. Surprisingly, anthropogenic activities have increased atmospheric CO₂ by 50% in less than 200 years, causing more frequent and severe rainfall, snowstorms, flash floods, droughts, heat waves, and rising sea levels in recent times. Hence, reducing the excess CO₂ in the atmosphere is imperative to keep the global average temperature rise below 2 °C. Among many CO₂ mitigation approaches, CO₂ capture using porous materials is considered one of the most promising technologies. Porous solid materials such as carbons, silica, zeolites, hollow fibers, and alumina have been widely investigated in CO₂ capture technologies. Interestingly, porous silica-based materials have recently emerged as excellent candidates for CO₂ capture technologies due to their unique properties, including high surface area, pore volume, easy surface functionalization, excellent thermal, and mechanical stability, and low cost. Therefore, this review comprehensively covers major CO₂ capture processes and their pros and cons, selecting a suitable sorbent, use of liquid amines, and highlights the recent progress of various porous silica materials, including amine-functionalized silica, their reaction mechanisms and synthesis processes. Moreover, CO₂ adsorption capacities, gas selectivity, reusability, current challenges, and future directions of porous silica materials have also been discussed.

In this study, two types of modified cassava starch samples (MCS and MWS) prepared from commercially available native cassava starch (NCS) and native cassava starch extracted using the wet method (NWS) were investigated for the removal of Pb(II) ions from aqueous solutions. MCS and MWS samples were synthesized under acidic conditions using Pluronic 123 as the structure-directing agent and tetraethylorthosilicate (TEOS) as the chemical modifying agent. Modified starch samples were characterized using Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), X-ray Diffraction (XRD), and a nitrogen (N₂) gas adsorption–desorption analyser. MCS and MWS showed enhanced thermal stabilities upon acid hydrolysis and chemical modification. The effects of contact time and initial Pb(II) concentration were studied through batch adsorption experiments. Adsorption kinetics followed the pseudo-second-order kinetic model. The equilibrium adsorption data were analysed and compared by the Langmuir and Freundlich adsorption models. The coefficient correlation (R²) was employed as a measure of the fit. The Langmuir model fitted well with equilibrium adsorption data, giving a maximum Pb(II) adsorption capacity of 370.37 and 294.12 mg/g for MWS and MCS, respectively. Modified samples exhibited a higher desorption efficiency of over 97%. This study demonstrated that modified starch could be utilized for Pb(II) removal from industrial wastewater.

As the major greenhouse gas, CO2 gas emission has been noticeably increased over the past decades resulting in global warming and climate change. As a result, it is imperative to reduce the excess CO2 in the atmosphere to hold “the increase in the global average temperature to well below 2°C (ideally 1.5°C) above pre-industrial levels set by the Paris Agreement on climate change. Among many ways, CO2 capture technology is considered as the most promising technology among the available technologies. Porous materials such as carbons, silica, zeolites, hollow fibers, and alumina are widely used as CO2 sorbents. However, among the available porous sloid sorbents, porous silica-based materials grabbed a significant attention due to their unique properties including high surface area, pore volume, good thermal and mechanical stability, and low cost. Therefore, development of porous silica materials as a promising CO2 absorbent is a continuously expanding research area in the current moment. Herein, we aim to visualize a full picture of the porous silica-based materials for CO2 capture. This review presents a comprehensive study of existing CO2 capture techniques and highlights the recent progress of different porous silica materials and synthesis processes. CO2 adsorption capacities of unmodified porous silica materials are less effective as compared with functionalized silica materials. Various research activities have been reported about functionalization of pours silica using amine groups. Therefore, in this review, different synthesis routes of amine-functionalized porous silica materials, CO2 adsorption capacities, gas selectivity and reusability were discussed. Moreover, the research challenges associated with the porous silica materials and future research directions are summarized.