The significance of carbon capture and storage (CCS) from greenhouse gas emission sources of Pakistan is described. Emissions are estimated from coal, oil, and gas power plants. Different sequestration technologies such as mineralization, geological storage, and oceanic storage are suggested. Current CCS running projects in Pakistan and challenges with solutions of CCS implementation are discussed.

An innovative correlation is proposed based on the Buckingham π theorem for prediction of CO₂ mass transfer flux in the reactive-absorption process using methyldiethanolamine solution. Effects of various parameters such as film parameter, CO₂ loading, concentration ratio, ratio of partial pressure to total pressure, film thickness ratio, and diffusion ratio are considered in this model.

An activated-carbon nanofibers/graphene nanocomposite was developed as adsorbent material with enhanced porous structure and high adsorption performance towards carbon dioxide. The graphene-based material used was synthesized from graphene-derived rice husk ashes, an abundant and cheap agricultural waste, providing an alternative for realizing green technology.

Activated carbon (AC) and hierarchically porous carbon (HPC) preparations were used as adsorbents for the removal of NH₃ after an amine-based post-combustion carbon capture process, and their adsorption capacities, adsorption rates, and stabilities were studied. In general, the HPC adsorbents with more mesopores and acid sites showed better performance and stability than the AC ones.

Polyether block amide/polysulfone composite membranes were prepared by the dip coating method and the effects of the coating speed and the solution concentration on the membrane performance were investigated. With increasing coating speed, the increasing withdrawal speed and the decreasing dipping time result in a thin selective layer at the appointed coating speed value.

The potential of compost derived from municipal solid wastes as a low-cost source of adsorbents for CO₂ capture was investigated. Five different samples were synthesized and screened regarding CO₂ uptake. One sample, which was chemically treated by sulfuric acid and thermally activated at 800 °C, had the highest breakthrough time and an adsorption capacity comparable to commercial carbon materials.

Amine absorption is still considered a state-of-the-art technology for gas industries. A technical analysis of gas-sweetening processes for natural gas with amine absorption has been conducted. An optimal point between amine concentration and circulation rate offers a great potential in this area for reducing the possibility of corrosion and foaming in the CO₂ removal system.

CO₂-based chemical production can contribute to climate protection and resource savings. A methodology for deriving suitable locations for CO₂-based chemical production in Germany, taking into account the local availability of CO₂ and renewable energy sources, is proposed. The location factors for a CO₂-based chemical production taking the example of olefin production are evaluated.

Membrane-based techniques emerged as the most effective option for the separation and/or capture of CO₂. Different types of membranes are reviewed with the main emphasis placed on mixed-matrix membranes with various types of fillers. Such membranes combine the advantages of both polymeric and inorganic membranes and exhibit the best performance for CO₂ separation from natural gas and other flue gases.

The idea is to interconnect energy generation from renewable energies (RE) with fossil energy from stations with low CO₂ footprints. These stations are capable of both base load operation and compensation for RE volatility and would produce both electricity and fuel, resulting in an improved overall efficiency from the combined energy production mix. The concept has a high degree of flexibility.

Thin-film composite mixed-matrix membranes are considered as an efficient separation technology for gas separation, fabricated as enhanced versions of mixed-matrix membranes. Recent advancements in these membranes are reviewed by comparing their performance in terms of permeability and selectivity. Various preparation techniques and their effect on the gas separation performance are described.

Empty fruit bunch (EFB) is utilized to increase the CO₂ capture capacity and enhance the cyclic stability of calcium oxide as an adsorbent prepared from waste cockle shells. The improvement of CaO as an adsorbent for cyclic CO₂ capture is explored by adding metal oxides from EFB. The average sorption decay could be also decreased due to the metal elements contained in the EFB.

An easily scaled-up spray-drying method was adopted to prepare Al-decorated and Al/Mg co-decorated CaO-based sorbents. Such spray-dried sorbents exhibit enhanced CO₂ capture performance. The stabilized performance is mainly attributed to the formation of Ca₁₂Al₁₄O₃₃, MgAl₂O₄, and MgO acting as skeleton structures to mitigate the sintering of CaCO₃ during carbonation/calcination cycles.

Based on systems modeling, three post-combustion CO₂ capture processes – membrane, absorption, and adsorption – were compared regarding energy consumption, design, and efficiency. The membrane process is revealed as the most efficient one in terms of energy consumption, but reaches lower recovery rates than the other two processes and a significantly smaller CO₂ purity than the absorption process.

Photosynthesis-based microalgal-mediated carbon dioxide capture and usage is a promising approach to reduce the amount of CO₂ in the atmosphere and provide a long-term and sustainable solution to global warming. To this end, freshwater microalgae Neochloris oleoabundans was cultured and the biomass and lipid productivity and lipid contents under different conditions were investigated.

Membrane technology is considered as an efficient, environmentally friendly, and inexpensive technology for CO₂ separation. Various approaches to improve membrane performance are reviewed with the focus on permeability and selectivity parameters. Polymer-inorganic nanocomposite membranes, metal organic frameworks, and ionic liquid mixed-matrix membranes are also discussed and evaluated.

Steel slag is a cheap and abundant raw material for preparing CaO-based sorbents for CO₂ capture by acidification. Orthogonal experiments were performed to optimize the acidification process to produce highly efficient CaO-based CO₂ sorbents with more stable sorption performance than natural limestone. Attrition-resistant sorbent pellets were produced by extrusion of sorbent powders.

Before natural gas can be transported and used, it is essential to remove impurities such as CO₂. In this work, polymer/zeolite (Pebax®-1074/DD3R) mixed-matrix membranes (MMMs) were fabricated for gas-separation applications. The performances of the MMMs were studied at different operating conditions and DD3R loadings. The separation performance of Pebax®-1074 was improved by using DD3R as a filler.

2-Methylimidazole, ethanol, and glycol are proposed for the modification of activated carbon for use in the separation of CH₄+CO₂ gas mixtures. The selectivity coefficient of the modified activated carbon was about five times higher than that of the fresh activated carbon. The CO₂ capture mechanism of 2-methylimidazole and glycol is outlined.

Commercial Portland cement (PC) was used as cheap binder to produce PC carbide slag (CS) pellets with enhanced mechanical strength. The carbonation conversion of the CS declined with the addition of PC, but the ability to resist sintering was improved. Extending the hydration time improved the CO₂ capture performance of the PCCS during pelletization.