A Comparison of Nitrate Release from Zn/Al-, Mg/Al-, and Mg–Zn/Al Layered Double Hydroxides and Composite Beads: Utilization as Slow-Release Fertilizers

Abstract

Nitrate-loaded Zn/Al, Mg/Al, and Mg−Zn/Al layered double hydroxides (LDHs) were synthesized using the coprecipitation method. The slow-release properties of LDHs were measured in powder form at various pH conditions. Sodium alginate was used to encapsulate Mg/Al LDH to produce composite beads (LB) to further slow down the release of nitrate ions. The prepared LDH samples and LB were characterized by X-ray diffraction, attenuated total reflectance Fourier transform infrared spectroscopy, thermogravimetric analysis, and inductively coupled plasma optical emission spectroscopy. The surface morphologies of LDHs and LB were obtained from scanning electron microscopy analysis. The slowrelease properties of the materials were evaluated using a kinetic study of nitrate release in tap water, soil solution, as well as plant growth experiments using coriander (Coriandrum sativum). The nitrate release ability of LDHs and LB was compared with a soluble nitrate source. The plant growth experiments showed that all three LDHs were able to supply an adequate amount of nitrate to the plant similar to the soluble fertilizer while maintaining the availability of nitrate over extended periods. The ability of LDHs to increase soil pH was also demonstrated.

Layered Double Hydroxides for Regulating Phosphate in Water to Achieve Long-Term Nutritional Management

“…The use of novel LDH-based adsorbents presents a promising approach for removing P from contaminated waters and developing slow-release P-fertilizers. However, the efficiency of LDH-based SRFs may be affected by soil profiles and climatic conditions, which trigger calls for exploring new LDH-based SRFs with high stability and long-term nutrients availability for plant uptake . Lohomusavi et al synthesized an environment-friendly hybrid nanocomposite based on LDH nanosheets and the banana peel cellulose- g -poly­(acrylic acid)/PVA (BPC-g-PAA/PVA) hydrogel for SRF of P and water retention .…”

“…However, the efficiency of LDH-based SRFs may be affected by soil profiles and climatic conditions, which trigger calls for exploring new LDH-based SRFs with high stability and long-term nutrients availability for plant uptake. 187 Lohomusavi et al synthesized an environment-friendly hybrid nanocomposite based on LDH nanosheets and the banana peel cellulose-g-poly(acrylic acid)/ PVA (BPC-g-PAA/PVA) hydrogel for SRF of P and water retention. 188 The P release behavior of the nanocomposite was investigated at various pH values ranging from 2 to 7, which showed an increasing trend with increasing pH until it reached its maximum value at normal pH.…”

Water-based synthesis and nitrate release properties of a ZrIV-based metal–organic framework derived from l-aspartic acid

“…1 Hydrogel formulations, ethylcellulose-coated granules of ammonium nitrate and nitrate-intercalated layered double hydroxides (LDHs) are among the solutions proposed in the literature for controlled release of nitrate fertilisers. 6–11…”

Water-based synthesis and nitrate release properties of a ZrIV-based metal-organic framework derived from L-aspartic acid

“…1 Hydrogel formulations, ethylcellulose-coated granules of ammonium nitrate and nitrate-intercalated layered double hydroxides (LDHs) are among the solutions proposed in the literature for controlled release of nitrate fertilisers. [6][7][8][9][10][11] The use of metal-organic frameworks (MOFs) in agriculture is attracting growing interest. [12][13][14] The porous nature of MOFs makes them suitable for use as host platforms for controlled release of both nutrients and pesticides, [15][16][17][18][19] as well as for their removal from the environment via either adsorption or degradation.…”