An overview of nanoclays or organically modified layered silicates (organoclays) is presented with emphasis placed on the use of nanoclays as the reinforcement phase in polymer matrices for preparation of polymer/layered silicates nanocomposites, rheological modifier for paints, inks and greases, drug delivery vehicle for controlled release of therapeutic agents, and nanoclays for industrial waste water as well as potable water treatment to make further step into green environment. A little amount of nanoclay can alter the entire properties of polymers, paints, inks and greases to a great extent by dispersing 1nm thick layered silicate throughout the matrices. The flexibility of interlayer spacing of layered silicates accommodates therapeutic agents which can later on be released to damaged cell. Because the release of drugs in drug-intercalated layered materials is controllable, these new materials have a great potential as a delivery host in the pharmaceutical field. The problem of clean water can be solved by treating industrial and municipal waste water with organoclays in combination with other sorbents like activated carbon and alum. Organoclays have proven to be superior to any other water treatment technology in applications where the water to be treated contains substantial amounts of oil and grease or humic acid.

Adsorption of an anionic dye, remazole brilliant blue R (RBBR) from aqueous solution, on organically modified attapulgite (ATP) and bentonite (BNT) clays was investigated. Beneficiated attapulgite and bentonite clay samples were modified by the cationic surfactant cetyltrimethylammoniumbromide (CTAB) by the ion exchange method. The efficiency of these adsorbents for the uptake of RBBR was examined by a series of adsorption isotherms using a batch technique at three different temperatures. A modified Freundlich equation has been proposed to describe the isotherms and compared with Langmuir, Freundlich and Redlich–Peterson (RP) models. Predicated values of RBBR adsorbed on modified clay using Freundlich, modified Freundlich, and RP models were identical along with the normalized standard deviation for all three models. These values were lower than those of Langmuir model. Values of r² for RP and modified Freundlich were found to be identical and better than that of Langmuir for all the isotherms. Adsorption of RBBR followed a pseudo second order kinetic model. Negative values of free energy change, ΔG indicated spontaneity of the adsorption of RBBR on both of organoclays. An increase in adsorption of RBBR with an increase in temperature may be attributed to activated adsorption and hence an endothermic process. This was further supported by positive values of heat of adsorption, ΔH. The adsorption capacity of modified attapulgite is lower than that of modified bentonite. However, considering the requirement of CTAB for modification of the clay, attapulgite is the more economical adsorbent than modified bentonite.

Herein, we report the facile synthesis of carbon hollow spheres (CHS) and reduced graphene oxide (rGO) from separators and graphite recovered from a spent lithium-ion battery (LIB), respectively, towards a “Waste-to-Wealth” approach. Subsequently, both CHS and rGO were employed to explore the gas storage capabilities for storing various gases such as N₂, H₂, and CO₂. For the first time, a facile one-step carbonization process was employed to concoct CHS from the recovered polymer separators without the use of a template. Similarly, the synthesis of rGO was undertaken entirely via the mended graphite and using the outer metallic Al cases as a reducing agent. The specific surface area and total pore volume of rGO and CHS were estimated to be 374 & 402 m² g⁻¹ and 0.16 & 0.30 cm³ g⁻¹, respectively. Moreover, the H₂ uptake at 15 bar and 77 K was found to be 1.78 wt% for rGO and 1.22 wt% for CHS. Interestingly, the acquired rGO from the waste constituents displays a high CO₂ uptake of 12 wt% and 33 wt% can be stored in the CHS at 40 bar and 298 K. This study affords the prospect of alternate/efficient gas storage materials by recycling spent LIB in an economically and environmentally friendly approach.