**2.1 Properties**

The characterization studies on magnesium borates make them preferable in industrial applications. These compounds are known for their superior thermal and mechanical strength, stability, and high coefficient elasticity. According to their specific characteristics, magnesium borates can be used as anticorrosive agent, catalyst, lubricant, and adsorbent. Due to their thermoluminescence properties, they also have applications in radiation dosimetry, X-ray screens, space research, and nonlinear optic laser systems [10–16].

Magnesium borates can be utilized in hydrogen storage systems, acoustic insulation, and ion-battery systems thanks to their high corrosion resistance. The viscosity of melted magnesium borates is relatively low and exhibits excellent electroconductivity. Therefore, magnesium borates can be used as either a coating agent on lithium-ion batteries or as an additive for electrolyte solutions [17–20].

For being of biocompatible properties of magnesium, magnesium borate compounds have also begun to be evaluated as a biomaterial for being unhazardous to the environment and human health. The eco-friendly behavior of these compounds increased their applications in health and wastewater treatments. Fan et al., studied the role of magnesium borate on stomach cancer chemotherapy as a hydrogen release agent [21]. Ma and Liu [22] experimented with the Congo Red adsorption from wastewater by using the sample of 2MgOB2O3H2O [22].

## *2.1.1 Thermoluminescence*

In nuclear research, dehydrated forms of magnesium borates such as MgB4O7, Mg2B2O5, and MgB2O4 are generally preferred. This can be explained by the decreasing hygroscopicity at reaction temperatures higher than 950°C and the ease of solidstate synthesis methods [11, 23–25]. Souza et al. [26] compared the thermoluminescence features of the synthesized magnesium borates in liquid-state and solid-state conditions and indicated better results of dehydrated samples [26]. MgB4O7 is the most studied composition among the magnesium borates, due to its thermoluminescence behavior. The studies on the thermoluminescence behavior of magnesium borates indicated their suitability of them in beta, neutron, and radiation dosimetry. Several rare earth elements of Cerium, Dysprosium, Samarium, Silver, Terbium, Thulium, have been doped to increase their efficiency in applications [23, 26–29]. Also, Prokic and Christeen [30] and Pellicioni et al. [31] experimented with the beneficial effects of graphite addition to magnesium borates; and the 3% graphite content was determined suitable for the optimum thermoluminescence [30, 31].

*Magnesium Borates: The Relationship between the Characteristics, Properties, and Novel… DOI: http://dx.doi.org/10.5772/intechopen.104487*

## *2.1.2 Mechanical strength*

Modification of thermoplastic materials with dehydrated magnesium borates can strengthen the tensile strength and strain failure. This situation can be explained with the increased physical crosslinking density and decrease in the size of bubble growth. For the mechanical strength increase, Mg2B2O5 is commonly preferred in literature [32]. Zhang et al. [33], analyzed the strengthening effects of magnesium borate addition on aluminum-based composites [33]. Baghebanadi et al., indicated the beneficial effects of dehydrated magnesium borates (Mg2B2O5 and Mg3B2O5) in addition to the cold crushing strength of magnesium-graphite composite [34].

## *2.1.3 Catalyst effect in reactions*

Catalyst effect of magnesium borates can be utilized to both increase reaction conversion in the reactions of hydrocarbon and/or they can also be evaluated to catalyze the other types of inorganic borates such as boron nitride [35, 36]. In the catalytic utilization of magnesium borate, the purity and the morphology of prepared magnesium borate are notable. In this case, the synthesis of magnesium borate at different morphologies will promote the comprehensive use of this type of compound.

Ahmad et al. [10], studied the catalyst effect of rod-like magnesium borates on the electrochemical activity of the dopamine enzyme [10]. Intemann et al. [13], used magnesium borates to catalyze the selective reduction of pyridine [13]. Loiland et al. [35], investigated the catalysis effect of magnesium borate complexes on the oxidative dehydrogenation of ethane and propane mixtures [35].

## *2.1.4 Adsorption behavior*

The determination of the adsorption behavior of magnesium borates is an up-andcoming practice among its applications. The few researches on the adsorption behavior of these compounds include the azo anionic dye of Congo red adsorption on the hierarchic porous particles of magnesium borates. According to the isothermal and kinetic estimations of the adsorption study, the adsorption mechanism can be explained with the Langmuir isotherm and Pseudo second-order kinetic model. The results also showed that adsorbents can be recycled with calcination at 400°C [22, 37, 38]. The comparison of maximum adsorbent capacity values (qM) for magnesium borates is presented in **Table 2**.

In the studies of Zhang et al. [22] and Ma and Liu [37] magnesium borates were fabricated in hydrothermal conditions whereas Guo et al. [38] preferred thermal conditions [22, 37, 38]. As it is seen in **Table 2**, it has been observed that hydrated compounds have a larger BET surface area and maximum adsorbent capacity. The results indicated that both hydrated and dehydrated forms of magnesium borates can be a promising candidate for toxic dye adsorption.

## *2.1.5 Thermal behavior*

Determination of thermal behavior for the magnesium borates could increase the evaluation probability as fire-retardant agents. Zhang et al. [39] studied the fire retardant effects of magnesium borate addition to the polyvinyl chloride (PVC) and lignin composite [39].


### **Table 2.**

*Comparison of maximum adsorbent capacity values for magnesium borates.*
