Bioremediation is a key process for reclaiming polluted soil and water by the use of biological agents. A commonly used approach aims to neutralise or remove harmful pollutants from contaminated areas using live microorganisms. Generally, immobilised microorganisms rather than planktonic cells have been used in bioremediation methods. Activated carbon, inorganic minerals (clays, metal oxides, zeolites), and agricultural waste products are acceptable substrates for the immobilisation of bacteria, although there are limitations with biomass loading and the issue with leaching of bacteria during the process. Various synthetic and natural polymers with different functional groups have been used successfully for the efficient immobilisation of microorganisms and cells. Promise has been shown using macroporous materials including cryogels with entrapped bacteria or cells in applications for water treatment and biotechnology. A cryogel is a macroporous polymeric gel formed at sub-zero temperatures through a process known as cryogelation. Macroporous hydrogels have been used to make scaffolds or supports for immobilising bacterial, viral, and other cells. The production of composite materials with immobilised cells possessing suitable mechanical and chemical stability, porosity, elasticity, and biocompatibility suggests that these materials are potential candidates for a range of applications within applied microbiology, biotechnology, and research. This review evaluates applications of macroporous cryogels as tools for the bioremediation of contaminants in wastewater.

Salinity, or accumulation of dissolved salts, is considered a significant problem affecting on agriculture section in Iraq generally and Basra particularly. Therefore, this research aims to explore the potential of eco-friendly materials to reduce soil salinity and enhance growing of plant. These materials are laboratory prepared and produced such as zeolite stone, humic acid and wood vinegar. Then, physical and chemical properties of saline soil were determined such as (pH, EC, Ca, Mg, Na, Cl, PO ₄ and SO ₄ ) before and after adding the synthesized eco-friendly materials divided into four groups (G1, G2, G3, G4) with three various ratios (1, 3, 5 g) for each kilogram of saline soil placed in pots that planted with Cress seeds ( Lepidium sativum) for observation and analysis. The results indicated remarkable improvements in soil characteristics. The best treatment was found in G4 combination of zeolite stone, humic acid and wood vinegar with added ratio (5g). The results showed a great achievement in reduction of electrical conductivity (EC) from approximately (~18 mS/cm to below 1.3 mS/cm) reflecting over 89% of salinity removal efficiency. Furthermore, pH levels of soil, which initially showed alkalinity (~8.3), were adjusted to be more optimal values around 6.8–7.2 depending on used material. Moreover, decrease the concentrations of elements that forms the main source for salinity in soil. Improvements were also recorded in growth of plants and nutrient retention. Statistical analysis by (one-way ANOVA test) showed a significant differences between groups with a significance level (P ≤ 0.05). These findings suggest that integrated use of zeolite, Humic acid, and wood vinegar could holds high potential for restoring the health of saline soils in southern of Iraq, however, more research are needed to explain and analyse the chemical reaction between these synthesized eco-friendly materials and salts of.