Enhancing the Ammonia Selectivity by Using Nanofiber PVDF Composite Membranes Fabricated with Functionalized Carbon Nanotubes.

Conventional hydrophobic membrane-based membrane distillation (MD) has been applied for ammonia recovery from an anaerobic digestion (AD) effluent. However, the typical hydrophobic membranes do not have selectivity for ammonia and water vapor, which results in high energy consumption from the water evaporation. To enhance the selectivity during the ammonia recovery process, the functionalized carbon nanotubes (CNTs)/polyvinylidene fluoride (PVDF) nanofiber membranes were fabricated by electrospinning, and the effects of different CNTs and their contents on the performance of nanofiber membranes were investigated.

Simultaneous biogas upgrading, CO sequestration, and biogas slurry decrement using biomass ash.

A novel system for simultaneous biogas upgrading, CO sequestration, and biogas slurry decrement was established by adding biomass ash into biogas slurry to form a renewable CO mixture absorbent. After CO saturation, the CO-rich mixture absorbent could be applied for plant growth. When the mass ratio of liquid to solid was 4:1, CO absorption capacity of this mixture absorbent reached up to 97.

A new approach for biogas slurry disposal by adopting CO-rich biogas slurry as the flower fertilizer of Spathiphyllum: Feasibility, cost and environmental pollution potential.

A new approach for biogas slurry disposal was put forward in this study through converting biogas slurry to the organic fertilizer of Spathiphyllum. The biogas slurry was firstly concentrated by vacuum distillation to reduce its volume by 80% who is called 5CBS, and then CO saturated to reduce its pH to about 6.50 ± 0.

Closing CO Loop in Biogas Production: Recycling Ammonia As Fertilizer.

We propose and demonstrate a novel system for simultaneous ammonia recovery, carbon capture, biogas upgrading, and fertilizer production in biogas production. Biogas slurry pretreatment (adjusting the solution pH, turbidity, and chemical oxygen demand) plays an important role in the system as it significantly affects the performance of ammonia recovery. Vacuum membrane distillation is used to recover ammonia from biogas slurry at various conditions.