Ca2+-Triggered Interaction of Amphiphilic Alginate and Soil to Facilitate Agrochemical Adsorption

Agrochemicals provide huge agronomic and economic benefits. However, excessive agrochemicals cause serious environmental pollution. The use of surfactants can effectively improve the utilization rate of agrochemicals in the soil, and an amphiphilic alginate derivative (Ugi-alg) was prepared in this work. This paper mainly discussed the affinity between Ugi-alg and soil colloids and the influence of Ugi-alg on the adsorption behavior of pesticides on colloidal particles. In the presence of 2.4 mM Ca2+, the affinity between soil colloids and Ugi-alg (30 mg/L) was enhanced (~ − 12.33 mV) compared with pure soil colloids (~ − 30 mV). The strong affinity between Ugi-alg and the colloids reduced the migration of acetamiprid. Transmission electron microscopy showed that soil colloids were wrapped by the network structure of Ugi-alg, indicating that Ugi-alg easily adhered to the surface of soil colloids. Studies of the adsorption showed the adsorption capacity of acetamiprid on soil colloids was 556 mg/g in the presence of Ugi-alg (30 mg/L) and Ca2+ (2.4 mM). And the adsorption behavior of acetamiprid in soil colloids was also not greatly affected by changes in pH and temperature. Ugi-alg is a degradable polysaccharide-based surfactant which provides a new concept and a practical method for the remediation of soil pollutants.Graphical abstract