The treated rice husk has been evaluated as a sorbent for removing lead (II) from aqueous solutions in fixed-bed studies. In this paper, the effects of flow rate (3 and 9 mL/min), bed depth (0.9, 1.8 and 2.8 cm) and influent lead concentration of (5 and 20 mg/L) on the adsorption capacity of the adsorbent in a fixed-bed column were investigated. The highest adsorption capacity (78 %) on a 20 mg/L Pb (II) solution was achieved within a flow rate of 9 mL/min and a bed depth of 2.8 cm. The experimental data obtained from the adsorption process was correlated with the Thomas, Adams– Bohart and Yoon–Nelson models. The results of the parameters indicated Adams–Bohart model fitted well over the other models.

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Clay minerals have been recognized as one of the cheap and effective materials for wastewater remediation. Among the various clay minerals, montmorillonite (MMT) has received much attention due to its wide availability, low-cost and promising properties such as high porosity, mechanical strength, and cation exchange capacity. Additionally, MMT has high swelling properties. These features make it an ideal material for wastewater remediation applications. In addition, it possessed good cationic exchange capacity, making it easier to interact with various molecules. MMT and its composites exhibited good selectivity and catalytic activity for contaminants elimination from wastewater. Surface modification and functionalization have been identified as a way to improve the MMT’s adsorptive performance and endow it with light and light-harnessing properties. Thus, MMT composites, especially metal and metal-oxide nanoparticles, have shown good adsorption and photocatalytic activity toward the elimination/mineralization of various contaminants such as dyes, pharmaceuticals, heavy metals, and other organic and inorganic species. As such, MMT and its composites can be adopted as potential materials for wastewater remediation.

Over the last century, there has been increasing debate concerning the use of biomass for different purposes such as foods, feeds, energy fuels, heating, cooling and most importantly biorefinery feedstock. The biorefinery products were aimed to replace fossil fuels and chemicals as they are renewable form of energy. Biomass is a biodegradable product from agricultural wastes and residues, forestry and aquaculture. Biomass could be sourced from a variety of raw materials such as wood and wood processing by-products, manure, fractions of organic waste products and agricultural crops. As a form of renewable energy, they have the advantages of easy storage, transportation, flexible load utilization and versatile applications. The aim of this study is to provide an overview for thermochemical and biochemical biomass conversion technologies that were employed currently. Attention was also paid to manufacture of biofuels because of their potentials as key market for large-scale green sustainable biomass product.

The abundant fraction of agricultural waste materials in the environment that poses disposal challenge could be converted into useful value added products such as activated carbon. Palm oil shell based carbon was prepared by two step process using K2CO3 as the chemical activant. The Langmuir surface area, BET surface area and pore volume were 817 m2/g, 707m2/g and 0.31cm3/g. From the FTIR analysis, carbonyls, alkenes and hydroxyls were identified. The SEM image shows gradual formation of pores due to elimination of volatiles and contaminants. Carbonization at 800°C for 2 hours and activation at same temperature for 1h has the highest yield of 23.27%. The proximate and ultimate analysis shows high percentage of carbon and low percentage of ash which is an indication of a good material for production of porous carbon. The activated carbon produced showed basic properties suitable for removal of organic contaminants in aqueous solutions. However, the aim of this study is to produce a green and porous carbon with controlled pores and surface properties for organic contaminants removal from water and wastewater.