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Several biocomposites were synthesized by copolymerizing hydroxyethyl methacrylate (HEMA) and itaconic acid (IA) at varied molar ratios in the presence of different wt% of collagen (CLG) and attapulgite (APG) clay. The structure and properties of the biocomposite adsorbents were characterized by Fourier transform infrared apectroscopy, nuclear magnetic resonance, X-ray photo electron spectroscopy, X-ray diffraction, scanning electron microscope, transfer electron microscopy, energy-dispersive X-ray analysis, differential thermal analysis-thermogravimetric analysis, point zero charge analysis, mechanical properties, and pH reversibility tests. The synthesis variables were optimized with a central composite design of response surface methodology (RSM). The biocomposite prepared with an optimized composition of 1.5 wt% CLG, 1.7 wt% APG, and 5:1 molar ratio of HEMA:IA showed an adsorption capacity ([Q.sub.e], mg/g) of 674.4/602.4 for methylene blue (MB)/Rose Bengal (RB) dye from a feed containing 200 mg/L of MB + RB dye mixture in batch mode. In a fixed bed in column mode, the optimized biocomposite showed a removal% of 82.8/71.3 for 100 mg/L inlet concentration, 20 ml/min flow rate, and 20 mm bed height with a breakthrough time of 23/31 min and a mass transfer coefficient ([k.sub.mtc] * [10.sub.5] cm/s) of 8.36/7.67 for MB/RB as single dye solution. KEYWORDS batch and column adsorption, biocomposite adsorbent, collagen and attapulgite, copolymer, mass transfer coefficient, RSM, 1 | INTRODUCTION Natural or semisynthetic polymers such as chitosan, starch, sodium alginate, or collagen (CLG) contain numerous functional groups such as hydroxyl (-OH), ketone (C=O), carboxyl (-COOH), or amines. [...]

The adsorption and heat-energy-aid desorption of methylene blue (MB) on a thermo-sensitive adsorbent of methyl cellulose/calcium alginate beads (MC/CABs) has been studied. The addition of methyl cellulose intensified the desorption ability of adsorbent, and boosted the difference of adsorption capacity of adsorbent between low temperature and high temperature. At the mass ratio of methyl cellulose to sodium alginate of 2:1, the difference of adsorption capacity of MC/CABs between 20 and 60°C reached 20.48 mg [g.sup.-1]. The effects of temperature, time and initial MB concentration on adsorption performance were investigated in detail. The MB adsorption on MC/ CABs followed the pseudo-second-order kinetic model. The equilibrium data was fitted well with Langmuir isotherm. The maximum adsorption capacity of 336.70 mg [g.sup.-1] exhibited MC/CABs had a good adsorption capability. Thermodynamic analyses showed high temperature was not favorable to MB adsorption, and MC/CABs had a distinct superiority in desorption of adsorbate with heat-energy-aid. Lastly, the possible mechanisms involving in adsorption and heat-energy-aid desorption were presented., INTRODUCTION Cationic dyes known as basic dyes are extensively used in dyeing of textile fibers such as cotton and polyester [1]. The complex aromatic molecular structures and xenobiotic properties of [...]