Study on an effective industrial waste-based adsorbent for the adsorptive removal of phosphorus from wastewater: equilibrium and kinetics studies

Fabrication of Ceramsite Adsorbent from Industrial Wastes for the Removal of Phosphorus from Aqueous Solutions

A more applicable adsorbent was fabricated using industrial wastes such as red mud, fly ash, and riverbed sediments. The heavy metal inside the raw materials created metal hydroxy on the adsorbent surface that offered elevated adsorption capacity for phosphorus. The required equilibrium time for the adsorption is only 10 min. The theoretical maximum adsorption capacity of the adsorbent was 9.84 mg·g−1 inferred from the Langmuir adsorption isotherm. Higher solution pH favored phosphorus adsorption. Kinetics study showed that the adsorption could be better fitted by the pseudo-second-order kinetic model. The presence of coexisting anions had no significant adverse impact on phosphorus removal. The speciation of the adsorbed phosphorus indicated that the adsorption to iron and aluminum is the dominating adsorption mechanism. Moreover, a dynamic adsorption column experiment showed that, under a hydraulic time of 10 min, more than 80% of the phosphorus in the influent was removed and the surplus phosphorus concentration was close to 0.1 mg L−1. The water quality after adsorption revealed its applicability in real treatment. Consequently, the adsorbent synthesized from industrial wastes is efficient and applicable due to the high efficiency of phosphorus removal and eco-friendly behavior in solutions.

Phosphorus removal from wastewater using eggshell ash

Eggshell ash was used as an adsorbent to remove phosphorus from wastewater. Adsorbent dose, initial phosphorus concentration, and contact time were investigated to determine the optimum conditions. Results indicate that 5 g of eggshell ash adsorbent with 1.5 mg L^-1 of initial phosphorus concentration removed over 90% of the phosphorus. When the temperature was increased, phosphorus removal potential also increased. Specific surface area, morphological features, and structure of the adsorbent were characterized by Brunauer-Emmett-Teller (BET) surface area analysis, scanning electron microscopy with energy dispersive X-ray spectrometer (SEM-EDS), and X-ray diffraction (XRD). Results showed prominent calcium, magnesium, and phosphorus in the eggshell ash surface after adsorption. The elemental composition of eggshell ash surfaces before adsorption did not contain phosphorus, revealing that calcium carbonate-based eggshell ash was co-precipitated with calcium phosphate. The adsorption mechanism was studied by applying Langmuir and Freundlich isotherm models. Experimental data fit well with the Langmuir model, which indicates monolayer adsorption. Eggshell ash was also applied as an adsorbent in wastewater at Srinakharinwirot University dormitories, resulting in 80% phosphorus removal within 2 h. These findings indicated that eggshell ash could be applied as an adsorbent for phosphorus treatment and removal from domestic and industrial wastewater.

Facile synthesis of novel 3D flower-like magnetic La@Fe/C composites from ilmenite for efficient phosphate removal from aqueous solution

In this study, a novel 3D flower-like La@Fe/C magnetic composite was successfully synthesized by carbothermal reduction of ilmenite via microwave radiation.