Distillers' Grains-loaded Clay Minerals In Hydrothermal Treatment Process And Products Application Research

With the rapid growth of zymurgy industry,the distillers'grains compositions were more and more complex,and a large amount of distillers'grains could not be digested directly as feed.However,composting and fuel utilization not only had high disposal cost but also had low added value,resulting in potential resources waste.In addition,according to the sustainable development needs,China was accelerating the green development of distillers'grains comprehensive utilization,encouraging the extending industrial chain and improving the products added value.As wet biomass waste,distillers'grains hydrothermal treatment(HTT)became a new effective treatment method,which could realize harmlessness,reduction and resource recovery.However,the preparation of distillers'grains hydrochar had some problems,such as poor adsorption performance and high nutrient content dissolution rate,which limited its practical application.Besides,a large amount of hydrothermal waste liquid was also an urgent problem to be solved.In this paper,the distillers'grains quality improvement by HTT were studied,and some research aspects were carried out:co-hydrothermal carbonization modification,adsorption experiment exploration,nutrient retention enhancement and waste liquid analysis and utilization.(1)Co-hydrochar was prepared by adding clay mineral materials and distillers'grains co-hydrothermal carbonization.It was changed that the raw hydrochar elemental composition and morphology,and solved that the problems of poor adsorption performance and nutrient loss.(2)The clay mineral materials and distillers'grains co-hydrothermal carbonization had good adsorption capacity.Compared with raw hydrochar,DG-A15(adding attapulgite)had the largest adsorption capacity of methylene blue and phosphorus,which were 340.3 and 97.4mg·g^-1,respectively.According to the characterization and adsorption model results,the co-hydrochar was controlled by adsorption mechanism,including electrostatic attraction,anion exchange and surface deposition.(3)The distillers'grains hydrothermal liquid product had potential as fertilizer.Different temperature,solid-liquid ratio and duration affected the liquid products properties.The optimal process parameters are as follows:temperature 200?,duration 1 h,solid-liquid ratio 10%.In addition,compared with the liquid products characteristics before and after the adding vermiculite,it was found that adding vermiculite reduced the nutrients extraction rate and release organic acids rate.(4)High nutrient capacity produced by distillers'grains and clay minerals co-hydrothermal carbonization,which could replace soilless culture substrate for seedling cultivation.The leaching capacity of NH₄⁺-N,NO₃^--N and PO₄^3-ranged from 25.0-38.0 mg·g^-1,7.0-19.0mg·g^-1 and 10.0-25.0 mg·g^-1,respectively.adding minerals hydrochar enhanced inorganic nutrients adsorption and had significant sustained release effect.In addition,the seedling experiment showed that DG II-V mixed substrates emergence rate was significantly higher than other substrates,and seedlings leaf length,plant height and root length were the best in the DG II-V mixed substrates.