Preparation of modified magnesium hydroxide and its application in the removal of Cr(III) from groundwater

Preparation of modified magnesium hydroxide and study on its removal of Cr(III) from groundwater With the increase of industrial activities, the problem of heavy metal pollution of groundwater is becoming increasingly serious, among which Cr(III) is a common pollutant. Magnesium hydroxide, as an environmentally friendly adsorbent, has a good ability to remove Cr(III). This paper introduces a preparation method of modified magnesium hydroxide and studies its performance in removing Cr(III) from groundwater.

1. Introduction

Cr(III) is a heavy metal ion that is harmful to human health and can accumulate through the food chain and have a negative impact on the ecosystem. Magnesium hydroxide shows great potential in removing Cr(III) due to its good adsorption capacity and environmental friendliness. The removal efficiency of magnesium hydroxide can be further improved by surface modification.

2. Materials and methods

2.1 Materials

Magnesium hydroxide: as a basic adsorbent.

Surface modifier: silane coupling agent, fatty acid, etc.

Cr(III) standard solution: used to simulate groundwater containing Cr(III).

2.2 Preparation of modified magnesium hydroxide

Precursor preparation: Prepare a certain concentration of magnesium salt solution (such as magnesium chloride or magnesium nitrate solution) and alkaline solution (such as sodium hydroxide or ammonia water).

Azeotropic distillation: Mix the magnesium salt solution and the alkaline solution in a certain proportion to induce a precipitation reaction to generate magnesium hydroxide. A surface modifier is added during this process.

Distillation process: The reaction mixture is placed in a distillation device and azeotropic distillation is performed under heating conditions to achieve surface modification.

Post-treatment: Wash and dry the modified magnesium hydroxide nanoparticles.

2.3 Cr(III) removal performance test

Adsorption experiment: A certain amount of modified magnesium hydroxide is added to a standard solution containing Cr(III), and adsorption experiments are performed under different conditions.

Analytical method: The concentration change of Cr(III) is determined by atomic absorption spectroscopy.

3. Results and discussion

Modification effect: The successful modification of the magnesium hydroxide surface was verified by characterization methods such as FTIR and XRD.

Cr(III) removal efficiency: The modified magnesium hydroxide showed significantly improved Cr(III) removal efficiency.

Analysis of influencing factors: The effects of factors such as pH value, contact time and adsorbent dosage on the removal rate of Cr(III) were investigated.

This study successfully prepared modified magnesium hydroxide and demonstrated its high efficiency in removing Cr(III) from groundwater. Through surface modification, not only the adsorption capacity of magnesium hydroxide was improved, but also its stability and applicability in practical applications were enhanced. This research result provides a new solution to the problem of Cr(III) pollution in groundwater.