The reasonable and effective application of waste tires and discarded concrete in concrete is an important branch of green concrete development. This paper investigates the effects of the inorganic modification mode on the basic mechanical properties of rubber recycled concrete based on indoor tests. Inorganic modification, such as water washing, acid washing, and alkaline washing modification, was mainly used to treat and modify rubber particles. The factors affecting the compressive strength, the splitting tensile strength, the flexural strength, the axial compressive strength, and the modulus of elasticity of modified rubber recycled concrete were analyzed. The study results show that the incorporation of recycled aggregates and rubber reduced the mechanical properties of concrete, with the compressive and splitting tensile strengths showing the greatest reductions of 27.36% and 27.24%, respectively. Three modification methods significantly improved the mechanical properties of rubber recycled concrete. The alkali washing modification method was the most effective, maximally improving the mechanical properties of rubber recycled concrete by 7.53-15.51%. The effects of the three modifications on the mechanical properties of concrete were ranked as follows: alkali washing > acid washing > water washing. This study provides a data basis for the practical application of rubber recycled concrete in engineering and a test basis for the development of green concrete.

Clay minerals are abundant on Earth and have been crucial to the advancement of human civilization. The ability of clay minerals to absorb chemicals is frequently utilized to remove hazardous compounds from aquatic environments. Moreover, clay-based adsorbent products are both environmentally acceptable and affordable. This study provides an overview of advances in clay minerals in the field of groundwater remediation and related predictions. The existing literature was examined using data and information aggregation approaches. Keyword clustering analysis of the relevant literature revealed that clay minerals are associated with groundwater utilization and soil pollution remediation. Principal component analysis was used to assess the relationships among clay mineral modification methods, pollutant properties, and the Langmuir adsorption capacity (Qmax). The results demonstrated that pollutant properties affect the Qmax of pollutants adsorbed by clay minerals. Systematic cluster analysis was utilized to classify the collected data and investigate the relationships. The pollution adsorption mechanism of the unique structure of clay minerals was investigated based on the characterization results. Modified clay minerals exhibited changes in surface functional groups, internal structure, and pHpzc. This review provides a summary of recent clay-based materials and their applications in groundwater remediation, as well as discussions of their challenges and future prospects.

It has long been known that starch as a raw material is of strategic importance for meeting primarily the nutritional needs of people around the world. Year by year, the demand not only for traditional but also for functional food based on starch and its derivatives is growing. Problems with the availability of petrochemical raw materials, as well as environmental problems with the recycling of post-production waste, make non-food industries also increasingly interested in this biopolymer. Its supporters will point out countless advantages such as wide availability, renewability, and biodegradability. Opponents, in turn, will argue that they will not balance the problems with its processing and storage and poor functional properties. Hence, the race to find new methods to improve starch properties towards multifunctionality is still ongoing. For these reasons, in the presented review, referring to the structure and physicochemical properties of starch, attempts were made to highlight not only the current limitations in its processing but also new possibilities. Attention was paid to progress in the non-selective and selective functionalization of starch to obtain materials with the greatest application potential in the food (resistant starch, dextrins, and maltodextrins) and/or in the non-food industries (hydrophobic and oxidized starch).

Starchy foods are an essential part of people\'s daily diet. Starch is the primary substance used by plants to store carbohydrates, and it is the primary source of energy for humans and animals. In China, a variety of plants, including edible medicinal plants, such as Pueraria root, yam tuber and coix seed, are rich in starch. However, limited by their inherent properties, kudzu starch and other starches are not suitable for the modern food industry. Natural starch is frequently altered by physical, chemical, or biological means to give it superior qualities to natural starch as it frequently cannot satisfy the demands of industrial manufacturing. Therefore, the deep processing market of modified starch and its products has a great potential. This paper reviews the modification methods which can provide excellent functional, rheological, and processing characteristics for these starches that can be used to improve the physical and chemical properties, texture properties, and edible qualities. This will provide a comprehensive reference for the modification and application of starch from medicinal and edible plants.

Photocatalytic conversion of CO2 into fuels such as CO, CH4, and CH3OH, is a promising approach for achieving carbon neutrality. Bismuth oxyhalides (BiOX, where X = Cl, Br, and I) are appropriate photocatalysts for this purpose due to the merits of visible-light-active, efficient charge separation, and easy-to-modify crystal structure and surface properties. For practical applications, multiple strategies have been proposed to develop high-efficiency BiOX-based photocatalysts. This review summarizes the development of different approaches to prepare BiOX-based photocatalysts for efficient CO2 reduction. In the review, the fundamentals of photocatalytic CO2 reduction are introduced. Then, several widely used modification methods for BiOX photocatalysts are systematacially discussed, including heterojunction construction, introducing oxygen vacancies (OVs), Bi-enrichment, heteroatom-doping, and morphology design. Finally, the challenges and prospects in the design of future BiOX-based photocatalysis for efficient CO2 reduction are examined.

Messenger RNA (mRNA) vaccines emerge as promising vaccines to prevent infectious diseases. Compared with traditional vaccines, mRNA vaccines present numerous advantages, such as high potency, safe administration, rapid production potentials, and cost-effective manufacturing. In 2020, two COVID-19 vaccines (BNT162b2 and mRNA-1273) were approved by the Food and Drug Administration (FDA). The two vaccines showed high efficiency in combating COVID-19, which indicates the great advantages of mRNA technology in developing vaccines against emergent infectious diseases. Here, we summarize the type, immune mechanisms, modification methods of mRNA vaccines, and their applications in preventing infectious diseases. Current challenges and future perspectives in developing mRNA vaccines are also discussed.

As a good passivation agent for heavy metals, modified biochar has been widely used in environmental remediation. In order to explore the effects of different modification methods on arsenic (As) and cadmium (Cd) passivation in soil by biochar, this study used co-precipitation and impregnation pyrolysis to prepare iron-modified biochar. Through adsorption experiments and soil culture experiments, the properties of biochar, adsorption capacity, and the As and Cd passivation ability in soil were analyzed. The results showed that both modification methods could increase the iron (Fe) content and zero charge point of biochar, and the Fe minerals supported by Fe-modified biochar (FeBC-1) prepared by co-precipitation were mainly Fe3O4, FeO(OH), and γ-Fe2O3. The Fe-modified biochar (FeBC-2) prepared by impregnation pyrolysis mainly consisted of α-Fe2O3 and γ-Fe2O3. FeBC-1 showed strong adsorption and removal ability for As and Cd, with a removal rate of 21.40%-34.14%, which could significantly promote the conversion of non-obligate adsorbed As to residual As in soil, whereas FeBC-2 only had a good adsorption effect on As. The adsorption capacity of BC, FeBC-1, and FeBC-2 for Cd were proportional to their CEC. The adsorption and removal effect of BC on Cd was better than that of FeBC-1 and FeBC-2, which could significantly promote the conversion of soil acid-soluble Cd to stable residue Cd.

Binary pollution of arsenic (As) and cadmium (Cd) has become the main soil environmental problem in China. As an adsorbent or immobilizer, modified biochar is playing an increasing role in the remediation of As and Cd-contaminated soil. Here, the limitations regarding the primitive biochar as an immobilizer for the remediation of As and Cd-contaminated soil were highlighted by this study. Meanwhile, the biochar modification methods for the remediation of As and Cd-contaminated soil were reviewed, and the main interaction mechanisms were analyzed. Finally, the prospects and questions for the future remediation of soil contaminated with As and Cd using modified biochar were proposed. The results showed that metal-modified biochar had a better synergistic effect on the remediation of As and Cd-contaminated soil and thus had better application prospects. The immobilization mechanisms of As and Cd using biochar material remediation were affected by its modification methods. For example, the mechanisms for (non)metal-modified biochar involved the functional group-induced bonding complexation, co-precipitation, and oxyanion As redox; for microorganism-modified biochar, the mechanisms were precipitation and As redox, and those for physical- and acid-modified biochar only included the physical adsorption and weak electrostatic attraction. In view of the limitations of present research on the application of modified biochar for the remediation of As and Cd-contaminated soil, future research is suggested to study the following:① the effect of biomass feedstock type, pyrolysis temperature, preparation conditions, cost, and soil aging; ② evaluation for stability and durability of heavy metal immobilization by modified biochar remediation under different environmental factors; and ③ insight to key remediation mechanisms of As and Cd-contaminated soil by material.

Many by-products originating from cereal, fruit and vegetable industries contain quite high amounts of dietary fiber (DF), which play an important role in maintaining the healthy state of the human body. Nevertheless, huge proportions of these by-products are still underutilized as feed ingredients, to generate energy within an anaerobic digestion plant or even landfilled. One of the biggest hindrances in the valorization of such by-products is their very low soluble dietary fiber (SDF) to insoluble dietary fiber (IDF) ratios, impairing their nutritional functionality, palatability and technological applicability. Therefore, it is of interest to develop methods that can enhance the SDF to IDF ratio and that can be applied to the by-product streams of the food industry, enabling better valorization perspectives for human nutrition purposes. In this regard, the review paper provides an overview of existing technologies to modify the SDF to IDF ratio in by-products of the food industry by means of physical, chemical and biological treatments. For each type of treatment, available data on application examples including achieved increases in SDF contents are given. Additionally, a comparative discussion regarding the advantages and disadvantages of these methods is provided.

With the rapid development of flexible electronic devices, flexible transparent conductive materials acted as the charge transport layer or electrical interconnect in the devices are of great need. As one of the representative conductive materials, poly(3,4-ethylenedioxythiophene) (PEDOT) has received more and more attention due to its high transparency in the visible region, good flexibility, especially the tunable conductivity. In order to achieve high conductivities, various of effective approaches have been adopted to modify the PEDOT thin films. However, some strategies need to be carried out in hazardous solvents, which may pollute the environment and even hinder the application of PEDOT thin films in emerging bioelectronics. Therefore, in this mini review, we focus on the discussion about the modification methods for PEDOT thin films in green solvents. According to the source of PEDOT, the modification methods of PEDOT thin films are mainly described from two aspects: 1) modification of in-situ PEDOT, 2) modification of PEDOT complex with poly(styrenesulfonic acid) (PEDOT:PSS). Finally, we conclude with the remaining challenges for future development on the PEDOT thin films prepared by green methods.