Basic and Reactive Dyes Sorption Enhancement of Rice Hull through Chemical Modification

Abstract

Problem statement: Many studies have been conducted on the removal of either anionic or cationic dyes. However, as a mixture of dyes does commonly exist together in wastewater, therefore it is of great interest to have a material that can remove both types of dyes. Approach: To prepare an inexpensive and efficient sorbent by chemically modifying rice hull for the removal of both basic and reactive dyes. Different chemical modifications were performed on rice hull and a comparison study on the uptake of dyes was carried out. Optimization study was carried out on most promising modified rice hull. Surface morphology of modified rice hull was examined and the functional groups present were determined using FTIR. Results: From the results, it appeared that by using EDA modified rice hull, an appreciable amount of both dyes could be sorbed. Varying the EDA/NRH ratios and heating temperatures affected the uptake of BB3 and RO16. The investigated sorbents were nonporous materials, due to the absence of pores and cavities. Sorption-desorption study showed that a complete recovery of BB3 can be obtained using high concentrations of H 2 SO 4 and HCl but the desorption experiments of RO16 using NH 3 and NaOH were not successful. Conclusion: The modification of rice hull with EDA under the optimum conditions (in a ratio of 1.00 g of NRH to 0.02 mole of EDA in a well stirred water bath at 80°C for 2 h) resulted in the formation of a sorbent (MRH) that could be used successfully to remove Both Basic (BB3) and Reactive dyes (RO16).

Azolla pinnata: An Efficient Low Cost Material for Removal of Methyl Violet 2B by Using Adsorption Method

“…Modification with the acids did not improve the removal of MV, and it may be due to the removal of certain soluble organic compounds [52] that favour the removal of MV. It was reported that not all modifications of adsorbent lead to higher adsorption capacities [53].…”

Removal of dyes using agricultural waste as low-cost adsorbents: a review

“…Hema and Arivoli (2007) used carbonized leaves of Pandanus with concentrated sulphuric acid in the weight ratio of 1:1 (W/V) for removing Congo red, Malachite green and Rhodamine B. Ong et al (2010) compared the efficiency of base-treated rice hull, hydrochloric acid-treated rice hull, quaternized rice hull, citric acid-treated rice hull, nitrilotriacetic acid-treated rice hull and ethylenediamine-modified rice hull for removing cationic dye BB3 and anionic dye RO16 from aqueous solution. Activated carbons were prepared from coconut shell, coir pith and rice husk using 1 M ferric chloride, 1 M trioxonitrate (V) acid, 1 M orthophosphoric acid and 1 M potassium carbonate as the chemical activating reagents for removing blue dye by Adekola and Adegoke (2005).…”

Adsorption of methylene blue from aqueous solution using untreated and treated (Metroxylon spp.) waste adsorbent: equilibrium and kinetics studies

“…However, the linear form of pseudo-second-order equation proposed by Ho and McKay [43] was found to be Cucumber peels 111.11 [11] Watermelon seed hulls 57.14 [11] Grape pulp 153.85 [15] Peanut husk 72.13 [46] Spent EDTA-modified rice husk 46.30 [23] Sago waste carbon 4.51 [41] HCL-treated meranti sawdust 120.48 [12] TA-modified bagasse 69.93 [13] NaOH-modified durian leaf powder 125 [14] q e and q t are the amounts of MB adsorbed (mg g -1 ) at equilibrium and at time t (min), respectively; k 1 (min -1 ) is the adsorption rate constant; k 2 (g mg -1 min -1 ) is the rate constant of second-order adsorption; k 1 d (mg/g h) is the intraparticle diffusion rate constant and C gives an idea about the thickness of the boundary layer; a (mg/g h) is the initial sorption rate and b (g/mg) is related to the extent of surface coverage and activation energy for chemisorption able to predict the behavior of the sorption process for all the range of concentrations studied here. The linear plots of t/q t against t (min) gives 1/q e (cal) as the slope and 1/k 2 q e 2 as the intercept, where k 2 (g/mg-min) is the rate constant of the second-order adsorption as shown in Table 8 and Fig.…”

“…These lignocellulosic byproducts possess various advantages, such as being ecofriendly, renewable, less expensive and abundantly available, as compared to commercial adsorbents [18,20]. Studies have also shown that chemical modification of agricultural by-products significantly enhances their ionbinding properties, thereby providing greater flexibility in their applications to a wide range of dyes [21][22][23][24]. However, while agricultural by-products are often presented as low-cost adsorbents, their availability is often region specific.…”