Exploration of the Optimum Rice Husk Biochar for Atrazine and 2,4-D Removal: Different Pyrolysis and Modification Conditions

In this study, the best RHB (rice husk biochar) was investigated through the effect of pyrolysis synthesis processes and modifications. Five biochars were synthesized from rice husk waste materials at different pyrolysis temperatures (400 to 600 °C) in oxygen-limited conditions. The biochars were modified by acids to remove minerals on the surface area. The characteristics of the biochars were determined including surface morphology, specific surface area, and functional groups. The herbicide adsorption was accomplished by the batch equilibration method. The result indicated that the biochar that synthesized 500 °C for 6 h had the highest maximum adsorption capacity. The optimum RHB was biochar modified with HF acid. The optimum biochar had less or no minerals and it achieved abundant functional groups on the surface areas. The pore volume distributions in pore sizes of micropores and narrow mesopores played an important role to perform the uptake of the herbicides, they were in the range of 7.90 % and 59.26 %, respectively. The high-efficiency removals of atrazine and 2,4-D by optimum biochar were 82.70 % and 95.10 %, respectively. The rice husk biochar is a suitable adsorbent to remove herbicides from the aqueous environment.Ostrav

Efficient heat batteries for performance boosting in solar thermal cooking module

Heat batteries show outstanding charging and discharging thermal energy capability with the latent heat of fusion (Hm) for solar thermal application. In this work, novel magnesium nitrate hexahydrate (MNH) based heat batteries are fabricated and tested for 1000 sequential thermal cycles. The MNH heat batteries demonstrate a high level of operational stability with the least corrosive rate. Real-time performance of the heat batteries was studied by incorporating them in the parabolic solar thermal cooking module. The developed MNH heat batteries based solar cooking module illustrates excellent heat retention capacity over 6 h after the sunshine. Temperature profiles under no load and full load conditions reveal the moderation and enhancement in the solar thermal cooking module's operational efficiencies. The solar cooking module's efficiency with the heat batteries reaches a maximum of 22.8% and 42.5%, under no load and full load conditions, respectively. Real-time cooking capacity with different edible materials under both outdoor and indoor environments proves the effective performance. Further, it is estimated that MNH heat batteries can be in full performance for a minimum of 2 years with maintenance-free and emission-free operations

Co-culture of microalgae-activated sludge for wastewater treatment and biomass production: Exploring their role under different inoculation ratios

In this study, mixed culture (microalgae:activated sludge) of a photobioreactor (PBR) were investigated at different inoculation ratios (1:0, 9:1, 3:1, 1:1, 0:1 wt/wt). This work was not only to determine the optimal ratio for pollutant remediation and biomass production but also to explore the role of microorganisms in the co-culture system. The results showed high total biomass concentrations were obtained from 1:0 and 3:1 ratio being values of 1.06, 1.12 g L-1, respectively. Microalgae played a dominant role in nitrogen removal via biological assimilation while activated sludge was responsible for improving COD removal. Compared with the single culture of microalgae, the symbiosis between microalgae and bacteria occurred at 3:1 and 1:1 ratio facilitated a higher COD removal by 37.5-45.7 %. In general, combined assessment based on treatment performance and biomass productivity facilitated to select an optimal ratio of 3:1 for the operation of the co-culture PBR