This work presents recent developments of algal bioreactors used for CO₂ removal and the factors affecting the reactor performance. The main focus of the study is on light intensity and photoperiods. The role of algae in CO₂ removal, types of algal species used in bioreactors and conventional types of bioreactors including tubular bioreactor, vertical airlift reactor, bubble column reactor, flat panel or plate reactor, stirred tank reactor and specific type bioreactors such as hollow fibre membrane and disk photobioreactors etc. are discussed in details with respect to utilization of light. The effects of light intensity, light incident, photoinhibition, light provision arrangements and photoperiod on the performance of algal bioreactors for CO₂ removal are also discussed. Efficient operation of algal photobioreactors cannot be achieved without the improvement in the utilization of incident light intensity and photoperiods. The readers may find this article has a much broader significance as algae is not only limited to removal or sequestration of CO₂ but also it is used in a number of commercial applications including in energy (biofuel), nutritional and food sectors.

The electric vehicle (EV) market in Pakistan faces a blend of challenges and opportunities as it transitions towards a more sustainable future. The transport sector, a significant consumer of carbon-intensive fuels (gasoline, diesel, CNG), contributes substantially to global GHG (greenhouse gas) emissions. In Pakistan, the shift to EVs is driven by the need to curtail the high cost of imported fossil fuels and the need to reduce carbon emissions. In this backdrop, this study conducts a market assessment of major challenges and opportunities that exist for EV uptake while also developing decarbonization pathways through scenario-based modeling using the Low Emission Analysis Platform (LEAP). Through a mixed-method approach, this study reveals that the key hurdles include the lack of charging infrastructure, the high costs of EVs, limited domestic production, and insufficient public awareness. Overcoming these challenges requires coordinated efforts in policymaking, infrastructure development, and public education. The successful adoption of EVs promises enhanced energy security, reduced environmental impacts, and economic benefits through decreased oil imports and lower operational costs.

To date, there are limited data on the thermal properties of secondary organic aerosol (SOA) components. In this study, we employed an experimental method to evaluate the physical properties of some atmospherically relevant compounds. We estimated the thermodynamic properties of SOA components, in particularly some carboxylic acids. The molar heat capacity, melting point and enthalpy, and vaporization enthalpy of the samples were determined via differential scanning calorimetry and thermogravimetric analysis, and their vaporization enthalpy (ΔH_vap) was estimated using Clausius–Clapeyron and Langmuir equations based on their thermogravimetric profiles. The thermodynamic properties of benzoic acid as a reference compound agree well with the reported values. The obtained specific heat capacities of benzoic acid, phthalic acid, pinic acid, ketopinic acid, cis-pinonic acid, terpenylic acid and diaterpenylic acid acetate (DTAA) are 118.1, 169.4, 189.9, 223.9, 246.1, 223.2, and 524.1 J mol⁻¹ K⁻¹, respectively. The ΔH_vap of benzoic acid, phthalic acid, ketopinic acid, DTAA, and 3-methylbutane-1,2,3-tricarboxylic acid (3-MBTCA) are 93.2 ± 0.4, 131.6, 113.8, and 124.4 kJ mol⁻¹, respectively. The melting and vaporization enthalpies of the SOA components range from 7.3 to 29.7 kJ mol⁻¹.

The co-contamination of aquatic systems with antimony (Sb) and humic acid (HA) is a global concern due to their potential risks to human health and environment. In this research, three-level-three-variable Box–Behnken design (BBD) was investigated for simultaneous Sb(III) and total organic carbon (TOC) removal responses from groundwater by use of ferric chloride (FC) as a coagulant. This study focuses on three operating variables, including initial Sb(III) concentration (100, 550, and 1000 μg/L), HA concentration (2, 6, and 10 mgC/L) and FC dosages (20, 60, and 100 mg/L). The proposed quadratic model presented good correlation with experimental values having R² and adjusted R² values of response variables (Sb(III): 0.9981 and 0.9956) and (TOC: 0.9935 and 0.9851), respectively. The most pronounced influence of FC dosage was observed in the removal responses of TOC and Sb(III). Interestingly, the model revealed that a high level of FC dosage had the same TOC removal potential regardless of increasing HA concentration. The statistical model for both Sb(III) and TOC responses was used to optimize the experimental conditions. Moreover, the experimental results were successfully validated with predicted values having high accuracy. The sludge volume produced for studied variables followed the decreasing order as FC dosage > HA concentration > Sb(III) concentration. Under optimum conditions, 0.45 mL/L sludge volume was produced in the treatment of ground water in Nawabshah. In general, the results of the current study may provide some insights into the predictability of simultaneous removal performance of Sb species and organic substances from groundwater.