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The production of low-cost solid adsorbents for carbon dioxide (CO2) capture has gained massive consideration. Biomass wastes are preferred as precursors for synthesis of CO2 solid adsorbents, due to their high CO2 adsorption efficiency, and ease of scalable low-cost production. This review particularly focuses on waste biomass-derived adsorbents with their CO2 adsorption performances. Specifically, studies related to carbon (biochar and activated carbon) and silicon (silicates and geopolymers)-based adsorbents were summarized. The impact of experimental parameters including nature of biomass, synthesis route, carbonization temperature and type of activation methods on the CO2 adsorption capacities of biomass-derived pure carbon and silicon-based adsorbents were evaluated. The development of various enhancement strategies on biomass-derived adsorbents for CO2 capture and their responsible factors that impact adsorbent's CO2 capture proficiency were also reviewed. The possible CO2 adsorption mechanisms on the adsorbent's surface were highlighted. The challenges and research gaps identified in this research area have also been emphasized, which will help as further research prospects.
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The utilization of organic matter (OM) to produce biogas is an attractive alternative for promoting sustainable development, addressing energy shortages and waste disposal problems, creating jobs, and investing in sanitation systems. Thus, this alternative is becoming increasingly important in developing countries. This study investigated the perceptions of residents in Delmas district, Haiti, regarding the use of biogas produced via human excreta (HE). A questionnaire containing closed- and open-ended questions was administered for this purpose. Sociodemographic aspects had no influence on locals' willingness to use biogas produced via different types of OM. The novelty of this research is that democratization and decentralization of the energy system are possible in the Delmas district using biogas produced from various organic wastes. Socio-characteristics of the interviewees did not influence their willingness towards a possible adopt biogas-based energy from several types of degradable organic matter. The results showed that more than 96% of the participants agreed that HE could be used to produce biogas and reduce energy shortages in their locality. In addition, 93.3% of the interviewees thought this biogas could be utilized for cooking food. However, 62.5% of respondents argued that using HE to produce biogas could be dangerous. Bad smell and fear of biogas produced via HE are the major concerns of users. In conclusion, this research could guide stakeholders' decisions to better address the problems of waste disposal and energy shortages and to create new jobs in the target study area. The research findings could help decision-makers better understand the willingness of locals to invest in household digester programs in Haiti. Further research is required to investigate farmers 'willingness to use digestates from biogas production.
Assuntos
Reatores Biológicos , Eliminação de Resíduos , Humanos , Haiti , Biocombustíveis , Eliminação de Resíduos/métodos , Fenômenos Físicos , AnaerobioseRESUMO
Production of indole-3-acetic acid (IAA) is well documented in various studies for the bacteria that inhabit the rhizosphere of plants, but with roots of wet rice, the outstandings have been not yet elucidated. This study began with the isolation of bacteria type strain Azospirillum sp. and developed the investigation to a screening of their ability in IAA production. This screening conducted a selection of only bacteria that was capable of the production of IAA with its content of over 25 µg. mL-1 for sequencing. Of 10 isolates only one resulted from the type strain Azospirillum brasilense (A. brasilense) with a similarity of 100%. Various factors that influence A. brasilense in biosynthesizing IAA such as temperature, pH, nitrogen presence and concentration of tryptophan in the culture medium were examined. The results indicated that the culture conditions were suitable for IAA biosynthesis at pH 6.5, 30 °C, culture media with nitrogen, and 0.1% trytophan. The next survey on the role of the immobilization of this bacteria with microalgae in alginate was highlighted to its support in microalgal growth. With the co-immobilization of bacteria and microalgae, the density of Chlorella vulgaris was significantly increased during 15-day culture, inducing 2.2 times of cell content in culture batch microalgae immobilized A. brasilense higher than that free-bacteria.
Assuntos
Azospirillum brasilense , Chlorella vulgaris , Microalgas , Oryza , Meios de Cultura , Ácidos Indolacéticos , Nitrogênio , VietnãRESUMO
Heavy metal pollution remains a global environmental challenge that poses a significant threat to human life. Various methods have been explored to eliminate heavy metal pollutants from the environment. However, most methods are constrained by high expenses, processing duration, geological problems, and political issues. The immobilization of metals, phytoextraction, and biological methods have proven practical in treating metal contaminants from the soil. This review focuses on the general status of heavy metal contamination of soils, including the excessive heavy metal concentrations in crops. The assessment of the recent advanced technologies and future challenges were reviewed. Molecular and genetic mechanisms that allow microbes and plants to collect and tolerate heavy metals were elaborated. Tremendous efforts to remediate contaminated soils have generated several challenges, including the need for remediation methodologies, degrees of soil contamination, site conditions, widespread adoptions and various possibilities occurring at different stages of remediation are discussed in detail.