Synthesis, characterization and biological applications of biosilica based composites

Agricultural wastes like sugarcane bagasse, rice husk, wheat husk, rice hull are the cheapest sources of biosilica (BS). In this study, sugarcane bagasse was used to extract biosilica by chemical treatment and combined with silk fibroin (SF), Polyurethane Foam (PUF) and TiO2 to prepare a novel biocomposites BS/SF/PUF and BS/SF/PUF/TiO2. The prepared biocomposites were analyzed using FT-IR and SEM analysis. The presence of various functional groups and the formation of biocomposites were confirmed by the FT-IR studies. The SEM analysis displayed rough surface morphology of the biocomposites. The antioxidant properties were studied using the DPPH assay. The biocomposites exhibited excellent antioxidant properties. The antimicrobial activities of the biocomposites were studied against three bacterial (Bacillus sp., Klebsiella sp. and Proteus sp.) and three fungal strains (Rhizopus sp., Aspergillus niger and Candida sp.). The results revealed that the prepared biocomposites were active against the selected bacterial and fungal species

Rice Hull-Derived Carbon for Supercapacitors: Towards Sustainable Silicon-Carbon Supercapacitors

A simple and effective mixing carbonization-activation process was developed to prepare rice hull-derived porous Si–carbon materials. The morphologies and pore structures of the materials were controlled effectively without any loading or additions at various carbonization temperatures. The structures of the samples changed from large pores and thick walls after 800 ∘C carbonization to small pores and thin walls after 1000 ∘C carbonization. An additional alkali activation–carbonization process led to coral reef-like structures surrounded by squama in the sample that underwent 900 ∘C carbonization (Act-RH-900). This optimal material (Act-RH-900) had a large specific surface area (768 m2 g−1), relatively stable specific capacitance (150.8 F g−1), high energy density (31.9 Wh kg−1), and high-power density (309.2 w kg−1) at a current density of 0.5 A g−1 in 1 M KOH electrolyte, as well as a good rate performance and high stability (capacitance retention > 87.88% after 5000 cycles). The results indicated that Act-RH-900 is a promising candidate for capacitive applications. This work overcomes the restrictions imposed by the complex internal structure of biomass, implements a simple reaction environment, and broadens the potential applicability of biomass waste in the field of supercapacitors.

Adsorption of Hydrogen Sulfide (H2S) from Municipal Solid Waste by Using Biochars

The emission of hydrogen sulfide (H2S) from municipal solid waste is one of the environmental issues that raised the public’s attention and awareness. Exposure to H2S that brings a foul smell of rotten eggs will cause headaches, irritation, dizziness, fatigue, and even death if the concentration of H2S is too high. The study’s goals are to investigate the properties of biochars made from rice hulls, banana peels, and sawdust; to compare the biochars’ physical and chemical properties; and establish the H2S removal efficiency of the three biochars. Biochars derived from rice hull (RHB-500), banana peel (BPB-550), and sawdust (SDB-500) by pyrolysis were used as the adsorbents. The biochar yield, pH, ash content, surface functional group, and morphology of the biochars produced were investigated. In this study, H2S was synthesized by mixing food waste and soil in the experimental column. The H2S produced was reduced by the adsorption method. The removal efficiencies of H2S for each biochar were determined by allowing the synthetic H2S to flow through the two columns that were packed with sand (act as control) and biochars, respectively. All biochars were alkaline, and BPB-550 had the highest pH, followed by SDB-500 and finally RHB-500. The order for removal efficiency of H2S (>94%) is BPB-550 > SDB-500 > RHB-500. Overall, the biochars derived from biomass had a strong ability to act as the adsorbents for H2S removal.

Formalin fumigation and steaming of various composts differentially influence the nutrient release, growth and yield of muskmelon (Cucumis melo L.)

Nutrient disorder and presence of disease-causing agents in soilless media negatively influence the growth of muskmelon. To combat these issues, use of environmentally-friendly sanitation techniques is crucial for increased crop productivity. The study was conducted under greenhouse and field conditions to investigate the effect of two different sanitation techniques: steaming and formalin fumigation on various media’s characteristics and their impact on muskmelon yield. Media: jantar, guar, wheat straw and rice hull and peat moss of 10% air-filled porosity and sanitized with formalin and steaming. Steaming of guar, jantar, and wheat straw increased the phosphorus (P) and potassium (K) concentrations by 13.80–14.86% and 6.22–8.45% over formalin fumigation. Likewise, P and K concentrations in muskmelon were higher under steaming. Steaming significantly inhibited the survival of Fusarium wilt sp. melonis, root knot nematode sp. meloidogyne and nitrifying bacteria in media than formalin fumigation. In conclusion, steaming decreased the prevalence of nitrifying bacteria and pathogens which thus improved the NO3−–N:NH4+–N ratios, P and K nutritional balance both in the media and muskmelon transplants. Hence, steaming as an environment-friendly approach is recommended for soilless media. Further, optimization of steaming for various composts with different crops needs to be investigated with steaming teachnique.

Optimizing the Fermentation Conditions and Determining the Disease Control and Growth Promotion Function of Bacillus Amyloliquefaciens 3-5

Bacillus spp. are helping to develop towards sustainable agriculture and have become a research hotspot in the field of plant pathology because they have great development potential such as control fungal plant diseases. Bacillus Amyloliquefaciens 3-5 was used as antagonistic bacteria in this experiment. The optimal medium for solid-state fermentation of B. amyloliquefaciens 3-5 contained bran (35%), rice hull powder (40%), corn gluten (20%), bean flour (15%), corn starch (1.5%), beef extract (2.5%) and MgSO4 (1.5%), and the optimal fermentation conditions included an inoculum of 6%, a solids content of 36 g/L, a feed-to-water ratio of 1:1, a fermentation temperature of 32 ℃, an initial pH of 7.0 and fermentation time of 44 h. When the dosage of the B. amyloliquefaciens 3-5 agent was 10%, the thick stems, root length and plant height of cucumber were significantly higher than those of the control (P＜0.05), and the growth rates were 77.45 %, 35.77 %, and 53.33 %, respectively in pot experiments. Compared with the control, and the preventive effect and therapeutic effect on cucumber Fusarium wilt were 72.09 % and 48.83 % by the application of B. amyloliquefaciens 3-5 agent，which showed that cucumber Fusarium wilt was successfully controlled by a newly isolated strain of B. Amyloliquefaciens 3-5. These results suggested that the prevention and control effect of B. amyloliquefaciens 3-5 agent on cucumber Fusarium wilt could not be underestimated.

Alkaline pre-treatment of rice hull and coconut hull using Response Surface Methodology

In this research, the rice hull and coconut hull from agriculture waste were investigated. The lignin content within the rice and coconut hull were determined before and after pre-treatment. Response Surface Methodology (RSM) used to predict the optimal condition for the treatments and Fourier Transform Infrared (FTIR) to identify the lignin content. The interaction of NaOH concentration, contact time (CT), and sample weight was investigated to optimize the lignin removal percentage (%). The correlation coefficient, R2 for a quadratic model of rice hull lignin removal was 0.8863 while for coconut hull lignin removal in the linear model was 0.7998, as well as the 2FI model was 0.8892. The optimum condition for rice hull lignin removal predicted by RSM were10 M NaOH concentration, 1-hour CT and 0.5 g sample produced 32.45% lignin removal. While for coconut hull lignin removal were 10 M NaOH concentration, 12 hours CT, 0.5 g sample produced 59.47% removal of lignin. Results show that alkaline pre-treated rice hull and coconut hull able to be used to remove higher percentage of lignin.