The impact of pyrolysis conditions on orange peel biochar physicochemical properties for sandy soil.

The citrus industry is considered one of the main contributors to agricultural waste. Peels are commonly used in the food industry or as feedstock in biorefining. In this study, the potential of waste orange peel biochar for agricultural applications in sandy soil was investigated. This will not only increase the percentage of agricultural waste recycling, but also lead to more sustainable agriculture with environmental benefits such as carbon sequestration. Biochar was produced through slow pyrolysis in the temperature range 300-600°C and at two holding durations (10 min and 60 min). Both factors had a significant impact on the physicochemical characteristics of biochar in the heating region 300-450°C. However, varying the holding time for pyrolysis temperatures beyond 450°C had a diminishing effect on biochar properties compared with the impact of increasing pyrolysis temperature. The study also looked at certain properties that are specific to agricultural application not previously reported for orange peel. Very high cation exchange capacities of 70 cmol kg-1 were achieved at 300°C, whereas water holding capacity was not strongly influenced by pyrolysis conditions. Preliminary planting tests indicate potential for improving agricultural sustainability in sandy soils. The technoeconomic analysis of biochar showed that the pyrolysis process can be profitable with sufficient plant capacity.

Influence of draw solution type and properties on the performance of forward osmosis process: Energy consumption and sustainable water reuse.

Single and multi-component fertilizers were used as a draw solution (DS) in forward osmosis (FO) to produce high-quality water from synthetic and seawater solution, eliminating the need for DS regeneration and reducing the operational energy. The effect of DS type, concentration, circulation flow rates on the FO water flux (WF), specific water flux (SWF), percentage water recovery (%Wrecovery), reverse salt flux (RSF) and percentage salt rejection (%R) were studied. The results showed that single fertilizer draw solution (SFDSs) produced higher WF (4.43 L/m2.h), %Wrecovery (30%) and RSF (60%) in comparison with multi-component draw solution (MCDS) with WF, %Wrecovery and RSF of 2.57 L/m2.h, 17% and 46%, respectively. DS with higher concentration produced the highest SWF and %Wrecovery and consumed less energy. MCDS with concentration of 200 g/L showed SWF in the range of 14.0 to 10.4 L/m2h and energy consumption of 0.312 kW/h m3 in comparison with 10 to 7.8 L/m2h and 0.23 kW/h m3 for MCDS with concentration of 100  g/L. Increasing the recirculation flow rate showed minimum effect on WF and up to 35% energy saving. Pure water extracted using liquid fertilizers utilizing the unique FO mass transport properties balanced nutrient requirement and the water quality parameters, thereby sustaining the aquaponics industry.