A dual-chamber microbial fuel cell (MFC) was fabricated and optimized for electricity generation. Titanium wire, graphite rod, and carbon cloth supported on stainless steel mesh were the best current collector, anode, and cathode electrode materials, respectively. To enhance the efficacy of the system, carbon-based materials in nano-scale (nanocarbonized materials) were prepared from pomegranate peel waste at different hydrothermal temperatures (300, 500, and 700 ^oC), and were used as anode coating material. The synthesized coating materials were characterized using EDX, FT-IR, Raman spectroscopy, XRD, TEM, fluorescence, UV, and XPS analyses. Data showed that nanocarbonized material prepared at 500 ^oC exhibited high surface area (682 m²/g), high pore size (122 nm), and indicated the presence of graphene oxide (GO) structure. The electrochemical behavior of MFC was monitored by cyclic voltammetry and impedance measurements. Results revealed that the anode coated with GO provided high MFC performance with a maximum voltage of around 1000 mV, and a maximum current of 0.1 mA, corresponding to a maximum power density of 12.46 W/m², which is 2.85-fold higher than that of a cell with a free graphite plate as an anode. Furthermore, the large charge transfer resistance and the low diffusive resistance observed upon coating the anode demonstrated the anode is functioning as a capacitor. The reported results proposed graphene oxide prepared from pomegranate peels as a novel coating anode material prepared from waste sustaining the idea of green curricular economy

Ammonia presence in water has many negative impacts including eutrophication. So, the major objective of this research was to evaluate the efficiency of microbial fuel cell (MFC) and electrochemical (ECS) systems for their removal and/or recovery from wastewater at different levels of ammonia (500 ppm, 1000 ppm, and 1500 ppm). Additionally, a novel approach was tested by using nanomaterial prepared from pomegranate peel as a coating material for the electrodes as it is abundant in many countries. Two systems were tested: Group (A) with a non-coated graphite plate anode (MFC1 and ECS1) and Group (B) which was coated with nano-graphene oxide made from pomegranate peels (MFC2 and ECS2). Results revealed that MFC1 gave the best ammonia removal efficiency reaching 96.2% when the initial concentration was 500 ppm after 13 days, and MFC2 gave maximum removal efficiency of 94.4% and 99.4% for 1000 and 1500 ppm after 19 and 25 days, respectively. COD results coincided with the removal efficiency. Electrochemical ammonia removal was carried out using two external electrical currents, 40 and 80 mA. Results showed that ECS2 gave the highest ammonia removal efficiency of 95.08% at 80 mA in case of 500 ppm, and the maximum for recovery was 80% when 1000 ppm was tested at 80 mA along with an increase in pH in the cathode chamber. Furthermore, ECS2 consumed less energy than ECS1 for ammonia recovery. ECS2 efficiently treated slaughterhouse wastewater reaching almost 100% ammonia removal; however, the maximum recovery of 44.7% occurred after 6 h, but consuming less energy than ECS1. It was evidenced that using an anode coated with nanographene oxide provided dual benefits of quickness and effective ammonia removal and/or recovery and provisioning energy requirements.

Though first-generation biofuels threaten the world’s food supply, biomass-derived green hydrogen is becoming an alternative to conventional fuels. Rice straw (RS) is a non-edible and a good feedstock for producing hydrogen because it has significant levels of carbohydrates, which are easily converted into fermentable sugars. Xylooligomers (XOS) are the most prevalent oligomers in hemicellulose and can be obtained via the chemical and biological hydrolysis of xylan. In this study, XOS were prepared from rice straw xylan (RS-based xylan) using a modified acid hydrolysis process, and the produced XOS, specifically xylotriose (X₃), was used for green hydrogen production using a cell-free synthetic enzymatic pathway (SythP) compared to commercial X₃. This study reported the first-time green hydrogen production using XOS extracted from RS-based xylan. The results showed a great XOS production pattern from RS-based xylan upon addition of 5 µl of 4% sulfuric acid to 2% RS-based xylan, followed by autoclaving at 121 °C for 30 min. The synthesized XOS were used to generate hydrogen through water splitting at 50 °C via SythP. The hydrogen generation rates were 2.948 and 2.68 mmol/l, respectively, energized by commercial X₃ and prepared X₃, respectively. Accordingly, the hydrogen production rate utilizing the commercial one is slightly higher, which confirms that XOS made from RS-based xylan do not inhibit enzymes and efficiently produce hydrogen. Consequently, using lignocellulosic biomass to synthesize valuable XOS and their further application as an energy carrier is a promising sustainable approach for enzymatic green hydrogen production using the cell-free synthetic enzymatic pathway (SythP).

Slaughterhouse wastewater (SW) contains high organic matter and nutrients, requiring sustainable treatment methods like forward osmosis (FO). This study evaluates the performance of four membranes: M1 (cellulose triacetate), M2 (M1 with carbon nanotubes), M3 (cellulose triacetate/diacetate), and M4 (M3 with carbon nanotubes) for treating SW. It reports the first-time use of CNTs in a hybrid membrane (CTA/CDA) for FO applications. Characterization showed that CNTs improved the mechanical and structural properties of M1, increasing the contact angle from 68 to 75 °C and roughness from 499.59 to 542.57 nm. However, for M3, the addition of CNTs in M4 decreased the contact angle from 88 to 77° and roughness from 773.088 to 620.001 nm. While CNTs enhanced hydrophilicity, they reduced permeability and fouling resistance due to fewer water transport channels. FTIR analysis revealed distinct stretching patterns correlating with variations in contact angles and membrane performance. The evaluation of membranes in forward osmosis (FO) comprised four phases. In Phase 1, membrane M3 excelled with 91.6% water removal and 0.32 LMH flux using 0.5 M MgCl₂, outperforming M4 at 80.84% and 0.28 LMH due to Mg²⁺ ion accumulation in M4. Phase 2 confirmed M3’s superiority with MgCl₂ among the four 0.5 M draw solutions. In Phase 3, M3 demonstrated an enhancement of 93.76% and 0.33 LMH with a 1 M solution., while M4’s performance reached 90.91% with 1 M NH₄HCO₃. Overall, low water flux was attributed to the lower circulation rates of feed and draw solutions. Phase 4 showed that M3’s water flux supported the growth of Dunaliella salina , while M4’s lower-salinity flux hindered it. This study explores the potential of hybrid membranes reinforced with carbon nanotubes (CNTs) for forward osmosis in treating slaughterhouse wastewater. It reveals a gap in data regarding CTA and CDA blends with CNTs, marking this as a new research area. The findings indicate that CNTs do not enhance the performance of hybrid membranes for this application; therefore, cost-effective membrane (M3) using recyclable solutes like NH₄HCO₃ present a promising solution for sustainable wastewater treatment.