Effects of NPK and Humic Acid on Growth and Yield of Melon under Semi-Arid Conditions of Kandahar

Abstract

Nitrogen-doped activated carbon (N-doped AC) from agricultural waste offers a low-cost route to solid sorbents for post-combustion CO₂ capture. However, there are limited straightforward and scale-up methods available to produce N-doped AC with large surface area, high nitrogen content, and strong CO₂ adsorption. Thus, this study aims to synthesize rice husk derived N-doped AC, by optimizing the surface morphology and nitrogen functionality to enhance CO₂ Capture efficiency and to quantifies adsorption, correlating the gains with BET surface area and microporosity. Rice husk was carbonized via pyrrole-assisted pyrolysis at 450  for 45 min with a 90 min dwell, the carbonized rice husk was then activated chemically using a 4:1 ratio of KOH to carbonized rice husk, heated to 800  at a ramp rate of 15  per min under a flow of N₂ gas at 150 ml/min for 60 min, Subsequently, N-doping was performed by immersing the activated carbon in a urea solution with a mass ratio of 4:1 (urea solution to AC) at 600  for 60 min. The obtained N-doped AC exhibits a remarkable surface area of 2986.6 m²/g and a significantly enhanced CO₂ adsorption capacity of 6.5 mmol/g under ambient conditions. Incorporating approximately 6% nitrogen into the carbon structure optimizes its porosity and structural properties. The integrated carbonization, activation, urea post-doping sequence provides a reproducible pathway to high performance, waste derived CO₂ sorbents, highlighting rice husk as a viable feedstock and underscoring the synergistic roles of micro/mesoporosity and nitrogen functionalities in boosting physisorption dominated CO₂ capture.