Sequestration of phosphate from water onto modified watermelon waste loaded with Zr(IV)

Removal of arsenic from semiarid area groundwater using a biosorbent from watermelon peel waste

Groundwater is one of the most important reservoirs in semi-arid and arid zones of the world, particularly in Mexico. The aims of this work were to produce a biosorbent from watermelon peel waste and a biosorbent with citric acid treatment and to evaluate both biosorbents with different concentrations of arsenic in groundwater. The biosorbents were produced with watermelon peel residues, which were observed by SEM microscopy to evaluate their physical morphology. Its removal potential was tested at concentrations of 0, 1, 13, 22, and 65 μg/L of arsenic, and both adsorption capacity and removal percentage were analyzed by final measurement obtained by atomic absorption spectrometry. The pH was measured throughout the experimentation maintaining ranges between 5.5 and 7.5. The biosorbent without treatment presented clearer and more compact flakes. At the microscopic level, the biosorbent without treatment presented pores with a more circular shape, and the biosorbent with treatment was more polygonal, similar to a honeycomb. The highest removal percentage was 99.99%, for both treatments at 4 h. The biosorbent without treatment at 4 h with arsenic concentrations of 65 μg/L presented the highest adsorption capacity (2.42 μg/g). It is concluded that watermelon peel biosorbent is a material that has the potential to remove arsenic from groundwater. This type of biosorbent is effective to remove arsenic and could be used in the field, however, it still needs to be optimized to convert it into a material completely suitable for large-scale use.

Efficient Sequestration of Cr(VI) from Aqueous Solution Using Biosorbent Derived from Arundo donax Stem

The potential of a biosorbent derived from Arundo donax stem, a readily available agricultural product, was examined to remove Cr(VI) from water. Various techniques such as XRD, FTIR, SEM, and EDX were used for the characterization of the prepared adsorbent. The optimal pH for Cr(VI) biosorption was found to be 2.0. The experimental data best suits the Langmuir isotherm model and pseudosecond-order kinetics. The maximum biosorption capacity (qmax) of the investigated biosorbent for Cr(VI) was evaluated to be 76.92 mg/g by the Langmuir model. From the results of the Cr(VI) biosorption using charred Arundo donax stem powder (CADSP), it can be a novel, cost-efficient, and effective material for removing Cr(VI) from water and wastewater.