Search

Pressure retarded osmosis (PRO) harnesses salinity gradient energy through the mixing of freshwater and saltwater, addressing the demand for sustainable energy sources. PRO typically utilizes river water or secondary wastewater as the feed solution, paired with seawater reverse osmosis (SWRO) brine as the draw solution. However, the limited availability of low-saline water presents a significant obstacle to energy generation. Therefore, the feasibility of a high-pressure PRO process utilizing seawater as the feed solution and hypersaline water as the draw solution was assessed to generate sustainable blue energy. Seawater has the potential to achieve the maximum extractable Gibbs-free energy through high-pressure PRO by maximizing the feed/draw ratio. The performance of the high-pressure PRO was theoretically evaluated, resulting in a tenfold increase in specific energy production compared to conventional SWRO-PRO due to the higher feed/draw ratio. However, high hydraulic pressure increased the membrane structural parameter and further reduced water flux and power density due to significant internal concentration polarization. Nevertheless, the high-pressure PRO process can achieve a power density exceeding 84 W/m2 when the structural parameter remains below 100 μm. The implications of the high-pressure PRO were further discussed to advance the concept of a blue circular economy, enhance environmental resilience, and promote sustainability. [Display omitted] • Feasibility of high-pressure PRO was investigated using seawater/hypersaline water. • Higher feed/draw ratio boosted energy production in the PRO process. • Seawater was assessed as a feed for high-pressure PRO for blue energy generation. • High-pressure operation raised the structural parameter reducing power density. • High-pressure PRO achieved >80 W/m2 at structural parameter <100 μm. [ABSTRACT FROM AUTHOR]

[Display omitted] • A sustainable conversion of plantation waste into syngas was achieved using CO 2 (key greenhouse gas). • CO 2 served a partial oxidant reacting with volatile pyrogenic products evolved from rubber tree residue, leading to enhancement of syngas, especially CO. • Oxidative functionality of CO 2 on syngas production was intensified in the presence of a nickel-based catalyst (Ni/Al 2 O 3). • Integrated process of catalytic pyrolysis and water–gas shift reaction notably increased H 2 productivity. This study introduces the sustainable recovery of energy from plantation waste by converting rubber tree residue (RTR) into syngas through carbon dioxide (CO 2)-assisted pyrolysis. The investigation centers on elucidating the specific impact of CO 2 on the pyrolysis of rubber tree residue, emphasizing its significant influence on enhancing syngas production. At temperatures ≥ 500 °C, CO 2 engages with volatile matters (VMs) released during the thermolysis of rubber tree residue, increasing carbon monoxide (CO) yields. To further optimize the process, catalytic pyrolysis setups incorporating additional heat (600 °C) and a nickel-based catalyst (Ni/Al 2 O 3) were implemented. These experimental configurations substantially increased syngas production from 19.51 to 24.24 mmol g−1, particularly amplifying CO yields under CO 2 conditions 2.58-fold compared to nitrogen (N 2) conditions. This enhancement is attributed to the partial oxidation of volatile matters facilitated by CO 2. Additionally, the Ni/Al 2 O 3 catalyst played a pivotal role in expediting the gas-phase homogeneous reaction of CO 2 with volatile matters, leading to further improved syngas production. Indeed, the syngas yield in the catalytic pyrolysis in the presence of CO 2 was 24.24 mmol g−1, which increased by 1.24 times in reference to the result under the N 2 environment. The identified functional role of CO 2 presents an opportunity to enhance the sustainability of waste management by optimizing carbon utilization and generating value-added products. [ABSTRACT FROM AUTHOR]