Recently, a team led by WU Zhengyan in Institute of Technical Biology and Agriculture Engineering, Hefei Institutes of Physical Science developed a slow-release herbicide using starch-regulated porous calcium carbonate microspheres.

In the past few decades, porous micro-nanomaterials have been developed as a tool for slow-release pesticides. Compared to traditional pesticides, they attracted much more attention due to their high pesticide utilization efficiency and few side effects.

A variety of carriers have been developed for slow-release pesticide systems including porous hollow silica, polymers, hydrogels, and others. Although those carriers could realize slow-release performance and improve the utilization efficiency of pesticides to different extents, their complicated processes and high cost limit their practical applications.

Therefore, it is necessary to design a carrier with low cost, easy processing, and satisfactory slow-release performance.

In WU’s research, porous calcium carbonate microspheres, or PCMs, fabricated through a facile coprecipitation method regulated by soluble starch (SS), were used as carrier for prometryn (PMT) to prepare slow-release PMT.

Under thermal treatment, SS molecules self-organized into nanoaggregates which binds Ca²⁺ through chelation and electrostatic interaction. Consequently, CO₃^2-, which produced CaCO₃ nanoparticles (CNPs) through heterogeneous nucleation regulated by SS aggregates was introduced to the system. Then PCMs-SS was formed.

Besides, the influences of SS concentration, reaction time and temperature on the morphology of PCMs-SS were optimized.

The resulting PCMs-SS possesses a large specific surface area and functional groups and thus could efficiently load PMT through electrostatic attraction and hydrogen bond.

Additionally, the slow-release characteristics of PCMs-SS realize effectively control of herbicide migration.

This PCMs-SS-herbicide could be applicable in the near future due to its higher utilization efficiency and control of weeds compared to traditional herbicide.

This research was supported by the National Natural Science Foundation of China, the Key Program of Chinese Academy of Sciences, the Youth Innovation Promotion Association of Chinese Academy of Sciences, the Science and Technology Service Programs of Chinese Academy of Sciences, and the Science and Technology Major Project of Anhui Province.

Link to the paper: Efficient synthesis of starch-regulated porous calcium carbonate microspheres as a carrier for slow-release herbicide

Schematic illustration for the fabrication and application of PCMs-SS/PMT. (Image by XIANG Yubin)

Contact:

ZHOU Shu

Hefei Institutes of Physical Science (http://english.hf.cas.cn/)

Email: zhous@hfcas.ac.cn