Superabsorbent hydrogels based on polysaccharides for application in agriculture as soil conditioner and nutrient carrier: A review

Abstract

a b s t r a c t Superabsorbent hydrogels (SH) continue being a very important issue in both academic and industrial fields due to their applications in several technologies. This is proved by the impressive number of publications, through papers and patents as well, dealing with SH. This review is targeted to update and discuss some important aspects of synthesis, characterization and application of SH in agriculture, mainly those based on polysaccharides, as soil conditioners and as polymer carriers for nutrient release. Basic properties of SH and some methods for chemically modifying polysaccharides are given and some directions for hydrogels preparation are highlighted as well. Mechanisms associated with water transport into the 3D matrix, taking into account the transference of mass from hydrogelsoil system to plant, are discussed in the light of some mathematical models. Release of nutrients either from granules coated by hydrophilic polymer or from SH, targeting applications in agriculture, is also discussed on the basis of often used mathematical models (the swelling-based kinetic models) and on a diffusion-based kinetic model with a partition activity coefficient. Examples of recent applications in agriculture as soil conditioners and carriers for nutrient release (fertilizers, etc.) are given. At the final, future trends and perspectives are considered. More than two hundreds references are cited in the whole text.

Potensi Kombinasi Teknologi Mutan Padi Toleran Kekeringan dan Polimer Superabsorben: Peran IPTEK Nuklir dalam Peningkatan Produksi Padi Lahan Kering

“…Penggunaan pembenah tanah (soil conditioner) merupakan satu diantara upaya-upaya pemulihan kualitas tanah [37]. Polimer superabsorben merupakan satu contoh bahan pembenah tanah yang mulai dikomersialisasikan sejak tahun 1980-an, terutama karena fungsinya untuk mempertahankan air dalam tanah, dan membawa nutrisi (tanaman dan tanah), lebih khusus karena memiliki karakter hidrofilik yang baik (high swelling capacity; high swelling rate), dan biokompatibilitas serta biodegradabilitas yang baik [38].…”

Polysaccharide-Based Nanocomposite Hydrogels With Zeolite: Evaluation of the Sorption Process of Pesticide Paraquat

“…Portanto, a porosidade, o grau de reticulação e densidade de cadeias são alguns dos fatores que afetam a capacidade de absorção do material. 8 Além desses fatores, as interações que influenciam o intumescimento do hidrogel também incluem a capilaridade, pressão osmótica e as forças de hidratação, as quais são contrabalanceadas pela força em resistir a expansão exercida pela cadeia reticulada do polímero. A magnitude de oposição dessas forças determina algumas características importantes do hidrogel como o ponto de equilíbrio de absorção de água, a resistência mecânica e a difusão interna.…”

Natural fibers for hydrogels production and their applications in agriculture

“…These components have allowed an increasing in the soil available water, which induce to fast growth (Gascue, Aguilera, Ramirez, Prin & Torres, 2006), prolong a plant survival under water stress (Cannazza et al, 2014;Cortés et al, 2007;Hüttermann, Orikiriza & Agaba, 2009;Mo, Shu-quan, Hua-min, Zhan-bin & Shuqin, 2006;Zhong, Zheng, Mao, Lin & Jiang, 2012) and have allowed a controlled release of fertilizers . One of the major limitations in hydrogels use for agricultural applications is the low mechanical resistance (Guilherme et al, 2015;Sannino, Demitri & Madaghiele, 2009). A pressure exerted by the plant and soil layer on the hydrogel, influences the loss of swelling capacity, elasticity and rigidity, respectively (Feng, Li & Wang, 2010).…”